Ann. Mus. Natl. Hist. Nat. 5: 19-27. 1804 - Type genus: Loasa Adans., Fam. pl. 2: 501. 1763.

Annual herbs, tiny rosette plants, vines, woody lianas, subshrubs, shrubs or small trees; erect, decumbend, or winding; woody or fleshy rhizome sometimes present, stem solid or filled with marrow, roots fibrous or tuberous. Indument usually including glochidiate hairs of some sort, often additionally with urticant setae, sometimes with glandular trichomes and uniseriate trichomes.
Phyllotaxy opposite in first leaves, then alternate or opposite, leaves usually petiolate, rarely sessile or subsessile or amplexicaul, exstipulate or pseudostipulate, lamina small to very large (to 50 cm long), linear, heart-shaped, ovate or circular, entire or variously divided, lobed, subpalmately divided, once to twice pinnatifid, margin serrate or mucronate, v. rarely entire, lamina membranaceous, chartaceous or coriaceous.
Inflorescences terminal dichasia or thyrsoids, rarely flowers apparently axillary (i.e. bracts foliose), bracts usually well developed, sometimes tiny, reduced or absent. Flowers bisexual, proterandric. Calyx tube conical to globose, very densely covered with trichomes, often with urticant setae; calyx lobes (4-) 5 (-7), free, green or rarely papery, usually persistent, sometimes enlarging after anthesis. Petals (4-) 5 (-7), free or united (sympetalous or pseudosympetalous), valvate or imbricate in bud, erect, spreading or reflexed, ovate, circular or spatulate, planar or deeply cymbiform, entire or irregularly serrate, sometimes with filiform appendages apically or longitudinal lamelliform flaps, thinly membranaceous to carnose, green, white, yellow, orange or red. Staminodia often present and very well differentiated: As single series with elongated filaments or petaloidly widened, or in episepalous groups of 3-12, forming elaborate complexes of 2-5 free staminodia and 3 (-7) staminodia united to form a floral scale (nectar reservoir), both staminodia and scales variously appendaged and ornate, staminodia sometimes with basal appendages, papillose, scales with calli, filiform appendages and/or saccate thickenings, sometimes winged apically, white, red, yellow, usually with colour patterns. Stamens (10-) 15-200 (-300), sometimes in epipetalous fascicles alternating with staminodial complexes, sometimes in epipetalous and episepalous fascicles, filaments filiform, sometimes very short. Anthers oblong to linear, laterally dehiscent, unifacial, bilocular, rarely unilocular, connective undifferentiated. Ovary inferior, rarely ½ to 2/3 superior, unilocular, with (0-) 3-5 (-7) parietal placentae; disc anular, fused with ovary roof, free apex of ovary later sclerified and frequently hispid (sometimes with urticant setae); ovules 1-¥ , in 1-¥ series on placentae. Style simple, filiform, stigma capitate or punctate.
Fruit chartaceous, coriaceous or lignescent, usually dehiscent, very rarely indehiscent, globose, conical or cylindrical, straight or narrowly twisted, opening with 3-7 apical valves and/or 1- 7 longitudinal sutures. Seeds 1-¥, very variable in size and shape, always dark brown with reticulate testa, sometimes winged.

Approximately 292 species in ca. 15 genera distributed in both Americas, one genus with two species in Africa, one genus with three species on the Marquesas Islands (Polynesia). The family as here defined falls into two different subfamilies:
 
 

syn Loasaceae subf. Cnidonieae Lk., Denkschr. R. Bot. G. 3: 209, nomen nudum
syn. Loasaceae subf. Mentzelioideae Lk., Denkschr. R. Bot. G. 3: 209, nomen illegitimum

With the characters of the family but never trees, petals always free, and either deeply cymbiform or carnose (never planar and membranaceous), sometimes with longitudinal lamelliform flaps, sepals always green. Staminodia in episepalous groups of 3-13 always present, free or forming elaborate complexes of free staminodia and staminodia united to form a floral scale, staminodia and scales variously appendaged and ornate, staminodia sometimes with basal appendages, papillose, scales with calli, filiform appendages and/or saccate thickenings, sometimes winged apically, white, red, yellow, usually with colour patterns. Style simple, filiform, stigma with three to five parallel stigmatic lobes.
Fruit lignescent, coriaceous or chartaceous, usually dehiscent (rarely indehiscent), globose, conical or cylindrical, straight or narrowly twisted, opening with 3-7 apical valves and/or 1- 7 longitudinal sutures.

Approximately 200 species in 15 genera, mostly South American, but 4 spp. in Central America, 3 spp. in Polynesia and 2 spp. in Africa. Subfamily Loasoideae has been subdivided into three tribes (Urban & Gilg 1900), but one of them, Kissenieae, is here reduced under Loaseae, because it does not seem justified to recognize a tribe on the basis of the reduction of seed number per fruit alone. The two tribes here recognized, Loaseae and Klaprothieae, are most easily distinguished by flower merosity (penta- versus tetramerous) but it may ultimately turn out that tetramerous Klaprothieae arose from within Loaseae.
 
 

Syn. Blumenbachieae Rchb., Handb.1837: 232, nomen nudum
Syn. Kissenieae Urb. & Gilg, Nova Acta Acad. Caes. Leop.-Carol. German. Nat. Cur. 76: 9. 1900. - Type genus: Kissenia Endl.
Genera: Aosa, Blumenbachia, Caiophora, Chichicaste, Huidobria, Kissenia, Loasa, Presliophytum, Scyphanthus.

Stinging hairs often present, fruits dehiscent, with numerous seeds, flowers 5-8-merous, petals without longitudinal lamellae, 1-3 x as large as sepals.
 
 

Nasa and the Conquest of South America: 214. 1997. - Type species: Aosa parviflora (DC.) Weigend º Loasa parviflora DC., Prodr. Syst. Nat. 3: 342. 1828.
Reference: Urban 1910 (as Loasa); Weigend 1997a (as Loasa); Weigend, in prep.

 Shortlived annuals, perennial herbs or shrubs, stinging hairs present. Leaves opposite below, often spirally inserted above, oblong, ovate to suborbicular, lamina lobed or entire, margin variously crenate or serrate. Flowers in complex terminal thyrsoids with monochasial or rarely dichasial (A. uleana) paracladia, bracts always absent, flower pendent, 5-merous, petals deeply cymbiform, cream to green; flowers with 5 staminodial groups consisting of three outer staminodes fused to form a green and brown or red and yellow floral scale with three dorsal filaments, scale apex forming 3 lobes or entire and recurved, and two free staminodes; stamens in 5 epipetalous fascicles of 7-13 each, placentae simple; fruit inferior to ¾ superior, subglobose to clavate, sometimes curved (A. sigmoidea), opening with 5 apical valves; seeds with asymmetrical testa cells with concave periclinal wall at one end and convex periclinal wall at the other. 2n = 24 (Coleman & Smith 1969).

7 spp. from E. Brazil (6 spp) & Hispaniola (1 sp). This group of taxa is well characterized on the basis of its ebracteate inflorescences with very small flowers and also on the basis of its unique seed morphology (asymmetrical testa cells with a bulge at one end and a collapsed periclinal wall on the other). It shows no clear affinities to any particular other genus in Loasaceae but its pendent flowers with coloured nectar scales and specialized pollination by Colletid bees indicate a relationship to the Andean groups Nasa, Loasa and Caiophora.
 
 

Goett. Gel. -Anz. 3/171: 1706. 1805. - Type species: B. insignis Schrad., Goett. Gel. -Anz. 3/171: 1706. 1805.
= Gripidea Miers, Trans. Linn. Soc. Bot. 25: 235, tab. 28. 1866. - Type species: Gripidea aspera Miers, Trans. Linn. Soc. Bot. 25: 235, tab. 28. 1866.
Reference: Weigend 1997a.

 Scandent or mat-forming, annual or perennial herbs, stinging hairs always present. Leaves always opposite, usually widely ovate, subpalmately lobed, sometimes bipinnatisect. Root system fibrous, rarely primary root developing into root tuber. Flowers each with two, non-recaulescent bracts in terminal thyrsoids with dichasial or monochasial branches (Blumenbachia sect. Angulatae) or dichasia (Blumenbachia sect. Gripidea) or borne singly (Blumenbachia sect. Blumenbachia), flowers pendent, 5-merous, petals deeply cymbiform, white; floral scale with three long, dorsal, filiform appendages, white, red and yellow, two free staminodes s-shaped, white and red; stamens in 5 epipetalous fascicles of 10-15 each, placentae simple. Fruit inferior, cylindrical to globose, always twisted anti-clockwise only, opening with longitudinal slits, seeds angular and with irrgularly rugose testa (Blumenbachia sect. Angulatae) or testa fibrous with very narrow testa epidermis cells (Blumenbachia sect. Blumenbachia), or testa widely reticulate, usually with two terminal wings (Blumenbachia sect. Gripidea). 2n = 24, 26(?) (Poston & Thompson 1977, Grau 1988)

12 spp., Brazil, Uruguay, Paraguay, Argentina, Chile. The genus Blumenbachia as here defined contains all Loaseae with fruits twisted anticlockwise only. Two of these groups were until recently considered as parts of Caiophora, but phytochemically, cytologically, morphologically and ecologically they clearly belong together with Blumenbachia. The typical section is clearly the most derived group with regards to inflorescence morphology (terminal inflorescences reduced to single terminal flowers) and fruit morphology (septifragous capsules with spongiose capsule walls, unique in the family).
 
 

Reliq. Haenk. 2: 41, tab. 42. 1836. - Type species: C. contorta (Desr.) K.Presl, Reliq. Haenk. 2: 41, tab. 42. 1836. (sphalm. Cajophora).
syn. Raphisanthe Lilja, Linnaea 15: 263. 1841. - Type species: Raphisanthe lateritia Lilja , Linnaea 15: 263. 1841.
syn. Illairea Lenné & C.Koch, Verh. Vereins Beförd. Gartenbaus Königl. Preuss. Staaten, N.R. 1: 397. 1853. - Type species: Illairea canarinoides Lenné & C.Koch.
Reference: Weigend 1997b.

Rosette plants, erect or scandent perennial herbs; primary root dominant, sometimes thickened, or primary and / or secondary roots forming root-tubers; stinging hairs always present. Leaves opposite, mostly ovate, pinnatifid or bipinnatisect, sometimes ternate (only C. hibiscifolia). Flowers in terminal symmetrical or highly asymmetrical thyrsoids or dichasia, rarely borne singly from basal rosette, bracts always leafy, flowers pendent, 5- to 8-merous, petals deeply cymbiform, white, yellow or red. Flowers with 5 staminodial groups consisting of three outer staminodes fused to form a floral scale, scale with or rarely without three long, often flag-shaped dorsal appendages and decorated with a double arch on back, sometimes scale reduced in size and simpler in structure (dorsal appendages lost, arches poorly differentiated), usually white, red and yellow, sometimes glassy green, two free staminodes s-shaped, white and red or yellow; stamens in 5 epipetalous fascicles of 10-15 each, placentae Y-shaped, ovules only on the proximal side. Fruit largely inferior, subglobose to narrowly cylindrical, frequently twisted, if so, then twisted antidromously, usually opening with 3-5 longitudinal slits, but sometimes opening with 3 apical valves (C. pulchella, C. nivalis), seeds with deeply pitted testa with fenestrate anticlinal walls. 2n = 14, 16 (Poston & Thompson 1977, Bruecher 1983, own data)Ca. 56 spp., Peru, Chile, Bolivia, Argentina, one species each in Uruguay, Brazil and Ecuador. Caiophora is essentially high Andean (above 3000 m), with only some of the southern representatives found as low as 800 m. It is a strongly diversified genus with some very variable and apparently actively diversifying groups (Caiophora sepiaria complex, Caiophora cirsiifolia complex etc.). Hybridisation is extremely widespread in this genus and even very distantly related species can and do hybridize in nature.
 
 

Nasa and the Conquest of South America: 215. 1997. - Monotypical: Chichicaste grandis (Standl.) Weigend º Loasa grandis Standl., J. Wash. Acad. Sc.17/1: 12. 1927.

 Erect, sparsely branched, short-lived herb, stinging hairs present. Leaves opposite below, alternate above, ovate with shallowly lobed and serrate margin, up to 40 cm long. Flowers in terminal thyrsoids with monochasial or rarely dichasial paracladia, bracts small, 2 per flower, flower erect, 5-merous, petals deeply cymbiform, cream to green; flowers with 5 staminodial groups consisting of three outer staminodes fused to form a white floral scale, scale apix forming 3-4 triangular lobes, white, two free staminodes white; stamens in 5 epipetalous fascicles of 15-20 each, placentae simple; fruit 1/3 superior, subglobose, opening with 5 apical valves, seeds angular, testa reticulate.

This is a tall rain-forerst herb (up to 4 m) found from NW Colombia to Costa Rica. It is one of the tallest Loasaceae and seems to be comparatively rare throughout its range. In spite of the lack of some crucial data (e.g. on cytology) it is clear that this is a very isolated taxon of the family and shares no exclusive derived characters with any other taxa.

Fl. Chil. 2: 440 (1847). =Loasa Sect. Huidobria (Gay) Urb. & Gilg, Nova Acta Acad. Caes. Leop.-Carol. German. Nat. Cur. 76: 256. 1900. - Type species: Huidobria chilensis Gay, Fl. Chil. 2: 440 (1847).
Reference: Grau 1997. Species Erect, densely branched annual herbs or shrubs from fleshy tap-root, stinging hairs always present. Leaves opposite below, alternate above, ovate to reniform with shallowly lobed and crenate margin. Flowers apparently irregularly alternating with foliage leaves (in reality inflorescences composed of complex assymmetrical dichasia), erect, 5-merous, petals deeply cymbiform, white to cream; flowers with 5 staminodial groups consisting of 5-7 outer staminodes fused to form a white floral scale, scale with 5-7 filiform dorsal appendages, completely white, free staminodes 3-5, white; stamens in 5 epipetalous fascicles of 10-15 each, placentae deeply divided into three lamellae. Fruit largely inferior, subglobose, opening with 4-5 apical valves; seeds numerous, testa striate or reticulate.. 2n = 36 (Grau 1997).

Two morphologically well differentiated species from the deserts of Chile. One annual, the other shrubby. Placentation, fruit shape, inflorescence strucure and ecology strongly suggest that this is the sister genus to the Peruvian Presliophytum. However, the differences in the shape of the floral scales and cytology seem sufficient to warrant recognition at generic level.
 
 

Gen. pl. suppl. 76. 1842. - Type species: Kissenia capensis Endl., gen. pl. suppl. 76. 1842.
syn. Fissenia Endl., var.orth., gen. pl. suppl. 76. 1842.
Reference: Dandy 1926.

 Erect, densely branched shrubs from fleshy tap-root. Leaves opposite below, often alternate above, petiolate, ovate to reniform with shallowly lobed and crenate margin. Flowers numerous in terminal dichasia or thyrsoids with 1-3 branches, erect, 5-merous, petals deeply cymbiform, cream, much shorter than sepals; flowers with 5 staminodial groups consisting of three outer staminodes fused to form an oblong scale, yellowish, and two free, slightly s-shaped staminodes; stamens in 5 epipetalous fascicles of 10-15 each. Fruit largely inferior, placentae recuced, ovoidal, indehiscent, crowned with conspicuously accrescent sepals. 2n = 24 (Poston & Thompson 1977).

2 species from Africa and the Arabian Peninsula, both growing in rocky and sandy areas in the desert.
 
 

Fam. pl. 2: 501. 1763.- Type species: L. acanthifolia Desr. - In Lam. Encyc. 3: 579-580. 1789.
References: Urban & Gilg 1900; Correa 1988; Sleumer 1955; Grau 1988, 1996; Grau & Bayer 1994.

 Rosette plants, erect or scandent annual or perennial herbs, sometimes with rhizome, stinging hairs always present, sometimes only few. Leaves opposite throughout or opposite below and alternate above, most often ovate, pinnatifid or bipinnatisect, sometimes widely ovate or subcircular and subpalmately lobed or ternate. Primary root dominant, forming a tap-root or thickened to form a root tuber. Flowers in terminal symmetrical or slightly asymmetrical thyrsoids or dichasia, rarely borne singly from basal rosette, bracts alwas leafy, flowers pendent, 5-merous, petals deeply cymbiform, white, yellow or red. Flowers with 5 staminodial groups consisting of three outer staminodes fused to form a floral scale, scale with or rarely without three long, often flag-shaped dorsal appendages and decorated with a double arch on back, usually white, red and yellow, two free staminodes s-shaped, white and red or yellow; stamens in 5 epipetalous fascicles of 10-15 each, placentae simple. Fruit largely inferior, cylindrical to subglobose, opening with 3-5 apical valves, seeds with deeply pitted testa with fenestrate anticlinal walls, rarely seeds large, globose and with rugose testa . 2n = 12, 24, 26, 36 (Grau 1988).

Ca. 36 species, mostly Chile, and adjacent Argentina, one species ranging into coastal Peru. The genus as here defined is still somewhat heterogeneous. Urban & Gilg’s series Macrospermae, Acanthifoliae, Floribundae, Acaules, Pinnatae, Volubiles and Deserticolae can safely be considered as closely related, but the two species Loasa malesherbioides Phil. and Loasa longiseta Phil. do not belong here and represent an independent lineage (flower and vegetative morphology, seed morphology and cytology indicate profound differences). They probably belong to the same group as Huidobria and Presliophytum (node 4 on the cladogram). However, the data currently available are insufficient for a decision. Caiophora and Scyphanthus are extremely closely related to the core of the genus Loasa: Upon a close examination the only differences which are valid are cytological: both Scyphanthus and Caiophora have fewer chromosomes than Loasa (Caiophora: 2n = 14, 16 vs. Loasa 26) but on the other hand seed and inflorescence morphology, growth habits and floral strucure are virtually identical, and the differences in fruit morphology between Caiophora and Loasa break down in a few Argentinian taxa (which are Caiophoras karyologically but have Loasa-fruits): It may ultimately be impossible to maintain Scyphanthus and Caiophora as distinct genera.
 
 

Nasa and the Conquest of South America: 214. 1997. - Type species: Nasa rubrastra (Weigend) Weigend º Loasa rubrastra Weigend.
References: Weigend 1996 (under Loasa), 1998, Weigend & Rodriguez 1998, Rodriguez & Weigend, in prep.

Annual or perennial herbs, subshrubs and shrubs, 5 to 400 cm tall; stinging hairs always present, primary root short-lived, root system dominated by adventicious roots from the decumbend basal stem portion. Leaves opposite or alternate, blades entire or variously divided, palmate or pinnatifid to bipinnate, sometimes peltate or reniform, margins denticulate or serrate. Flowers in terminal thyrsoids, dichasia or monochasia, each flower on the branches with one recaulescent bract; flowers pentamerous, corolla reflexed, spreading or narrowly campanulate, petals circular to narrowly ovate, planar or deeply cymbiform, white, yellow or orange; nectar scales variable, variously elaborated with up to three calli on back and / or apical wings, filiform appendages on back usually lacking, usually with coloured bands in green, white, yellow, orange, brown or bright red, always with two dorsal nectar sacs; staminodia variable, with or without basal appendages, often papillose, sometimes with clavate thickening at middle, white, yellow, sometimes with pink stripe; stamens numerous, in 5 epipetalous fascicles of 6-20 each, placentae simple; Capsule straight, globose to narrowly cylindrical, pedicel often elongated after anthesis, opening with 3-5 apical valves only or with apical valves and a longitudinal suture or functionally indehiscent; seeds with shallowly reticulate testa. 2n = 28, 56 (Diers 1961, Huyn 1965, own data on ca. 20 species).

Ca. 100 spp. in Central and South America: 3 spp. in Central America, ca. 20 in Colombia, 30 in Ecuador, over 50 in Peru, 2 in Bolivia. Nasa is the largest genus in the family, accounting for over one third of the species total. It is an essentially Andean group from the cloud forests, subparamo and the puna with only very few species at lower elevation or outside the Andes (e.g. Cordillera de Colonche, Ecuador). The vast majority of taxa is narrowly endemic to single mountains or narrow regions. Morphologically the genus is enormously variable including evergreen shrubs with hummingbird-pollinated, large, orange flowers and ephemeral plants which are self-pollinated. In spite of its variability it has an exclusive range of characters and shows no major morphological affinities to any of the other genera. The genus as such is most readily characterized by its unique cytology (n=14) and its characteristical inflorescences with one recaulescent bract per flower. The majority of the taxa has been described in the past few years.
 
 

Nasa and the Conquest of South America: 215. 1997. - Basionym: Loasa sect. Presliophytum Urb. & Gilg, Nova Acta Acad. Caes. Leop.-Carol. German. Nat. Cur. 76: 260. 1900. - Type species: Presliophtyum incanum (Grah.) Weigend º Loasa incana Grah.
References: Weigend 1997c. 1998.

 Erect, densely branched annual herbs or shrubs from fleshy tap-root, stinging hairs always present. Leaves opposite below, often alternate above, ovate to reniform with shallowly lobed and crenate margin. Flowers apparently irregularly alternating with foliage leaves (in reality inflorescences composed of complex asymmetrical dichasia), erect, 5-merous, petals deeply cymbiform, white to cream; flowers with 5 staminodial groups consisting of three outer staminodes fused to form a white, floral scale, scale with three long dorsal appendages, completely white, two free staminodes s-shaped, white; stamens in 5 epipetalous fascicles of 10-15 each, placentae deeply divided into three lamellae. Fruit largely inferior, subglobose, opening with 4-5 apical valves. 2n = 24 (Poston & Nowicke 1993, own data for all three species).

3 species from the desert of western Peru (below 2000 m), on rocky slopes. Two of them widespread, perennial shrubs, one (P. heucheraefolium) a very rare annual from Ancash and neighbouring Lima.
 
 

in Sweet, Brit. Fl. Gard. Ser. 1 Vol. 3: Tab. 238. 1828. - Type species: S. elegans D.Don, in Sweet, Brit. Fl. Gard. Ser. 1 Vol. 3: Tab. 238. 1828.

 Scandent annual herbs, stinging hairs always absent. Leaves opposite, widely ovate, bipinnatisect. Root system fibrous. Flowers in terminal, highly asymmetrical dichasia, bracts leafy, flowers erect, 5-merous, petals deeply cymbiform, bright yellow. Flowers with 5 staminodial groups consisting of three outer staminodes fused to form a floral scale, scale with three long, dorsal appendages and decorated with a double arch on back, white, red and yellow, two free staminodes s-shaped, white and red; stamens in 5 epipetalous fascicles of 10-15 each, placentae simple. Fruit inferior, narrowly cylindrical (more than 10x as long as wide), opening with longitudinal slits, seeds with deeply pitted testa with fenestrate anticlinal walls.

1-2 spp., Chile. This genus is very close to Caiophora in habit and morphology, differing essentially in its erect flowers and annual habit. For affinities see under Loasa.
 
 

Nova Acta Acad. Caes. Leop.-Carol. German. Nat. Cur. 76: 9. 1900. - Type genus: Klaprothia Kunth
Genera: Klaprothia, Plakothira, Xylopodia.

Leaves opposite, stinging hairs absent; fruits dehiscent to tardily dehiscent, seeds few to numerous; flowers erect or pendent, 4-merous, petals with 2 longitudinal lamellae each, white or green, 2-4 x as large as sepals.
 
 

In Humb., Bonpl. & Kunth, Nov. gen. sp. 6: 96: 1823. – Type species: Klaprothia mentzelioides Kunth.
= Sclerothrix K.Presl, Symb. Bot. 2(6): 3, t. 53. 1834. - Type species: S. fasciculata K.Presl.
Reference: Poston & Nowicke 1990.

 Erect or ascending annual or perennial herbs. Leaves opposite, petiolate, undivided, margin serrate. Flowers in complex terminal thyrsoids (K. fasciculata) or simple dichasia (K. mentzelioides), flowers erect, petals white; flowers with 4 staminodial groups with 2-6 staminodia each, 3-4 outer ones slightly connate basally or all free, very densely papillose-hairy, apex irregularly club-shaped and lobed, yellow; stamens in 4 epipetalous fascicles of 1-5-7 each; placentae simple. Fruit inferior, placentae simple, ovoidal and straight to slightly twisted (K. mentzelioides) and tardily dehiscent with apical valves or clavate and twisted (K. fasciculata) and opening with longitudinal slits. 2n = 24, 48 (Poston & Nowicke 1990).

2 species from Central into subtropical South America (S. to Brazil and Bolivia), Carribbean, Galapagos.
 
 

Adans. 7: 240. 1985. - Type species: Plakothira frutescens Florence.
References: Florence 1985: Adansonia 7: 240. Florence 1997: Allertonia 7(4): 238-253.

 Shrub or perennial herb with fibrous roots, branches lignescent to ligneous. Leaves opposite, petiolate, undivided, margin serrate. Flowers in terminal dichasia, erect, petals green or white; flowers with 4 staminodial antesepalous groups with 7-9 staminodia each or both in antesepalous and antepetalous position , 4-6 outer ones fused to form a green and yellow scale or free to base, often papillose-hairy; stamens in 4 epipetalous fascicles of 7-10 each or in epipetalous and episepalous fascicles, filaments 5-7 mm long, white, anthers tiny, pale yellow, placentae simple. Fruit semisuperior, subglobose, straight. 2n = 48 (P. parviflora, own data).

3 species, all from the Isles Marquise (Polynesia) and all of them recently described. The genus is doubtfully distinct from Klaprothia, at least while Sclerothrix – which is morphologically more distinct from Klaprothia mentzelioides than Plakothira – is retained in Klaprothia.
 
 

Nasa and the Conquest of South America: 215. 1997. – Monotypical: Xylopodia klaprothioides Weigend.

 Shrub with stiffly erect branches from horizontal xylopodia. Leaves opposite, petiolate, with 2-3 lobes on each side, margin serrate. Flowers in terminal dichasia, pendent, petals green; flowers with 4 staminodial groups with 7-9 staminodia each, 4-6 outer ones fused to form a green and yellow scale, densely papillose-hairy; stamens in 4 epipetalous fascicles of 7-10 each; placentae simple. Fruit semisuperior, subglobose, straight, opening with 4 apical valves. 2n = 24 (own data).

This very narrowly endemic and recently discovered genus is so far only known from Contumaza in Northern Peru. Its floral scales are very similar to those of Huidobria from Chile, but it is very well distinguished by vegetative morphology, inflorescence structure, flower merosity, petal structure, and fruit characters.
 
 

Basionym: Mentzelieae Rchb., Handb. Nat. Pfl. Syst.: 232. 1837. - Type genus: Mentzelia L., Sp. pl. 1: 516. 1753.
syn. Loasaceae subf. Bartonioideae Spach, Hist. nat. veg.: 233. 1838. - Type genus. Bartonia Sims, Bot. Mag. tab. 1487. 1804., nomen illegitimum.
syn. Eucnideae Urb. & Gilg, Nova Acta Acad. Caes. Leop.-Carol. German. Nat. Cur. 76: 8. 1900. - Type genus: Eucnide Zucch.

Annual or perennial herbs (most!), subshrubs, shrubs or small trees (only M. arborea); never winding, sometimes with annual shoots from a thick, underground xylopodium (Schismocarpus), phyllotaxy opposite in first leaves, then usually alternate, rarely opposite, leaves exstipulate, usually lobed, more rarely subpalmately divided, margin usually serrate or mucronate. Inflorescences terminal, dichasia or thyrsoids, bracts usually well developed and frondose, sometimes reduced, sometimes united with and sitting on the calyx tube (M. involucrosa). Flowers pentamerous, petals free or united (some Eucnide), planar or shallowly cymbiform, margin entire, never clawed, thinly membranaceous, white, yellow, orange or red, apically always apiculate. Staminodia, if present, free to base: a single series with elongated filaments or petaloidly widened. Stamens (10-) 15-200 (-300). Style simple, filiform, stigma capitate or punctiform. Fruit lignescent, coriaceous or chartaceous, pedicel sometimes dramatically elongating after anthesis and negatively phototropic. Capsule always apically dehiscent, never twisted.

Ca. 80 spp., Argentina and Chile to Canada. Urban & Gilg (1900) considered Eucnide as belonging to a separate tribe (Eucnideae) but Hempel (1997) has recently argued that Mentzelia is paraphyletic with respect to Eucnide, which automatically requires the reduction of the tribe Eucnideae under Mentzelieae and thus renders the subdivision into tribes superfluous.
 
 

Sp. pl. 1: 516. 1753. - Type species: Mentzelia aspera L. - Lectotype: Plumier (ed. J. Burmann), Pl. am. 7: 167, tab. 174. 1758
syn. Bartonia Pursh ex Sims, Bot. Mag.: Pl. 1487(1812), nomen illegitimum (non Bartonia Mühl. ex Wild., Gentianaceae 1801) - Type species: Bartonia decapetala Pursh ex Sims, nomen illegitimum.
syn. Nuttallia Raf., Am. Month. Mag. 175(1817). - Type species: Nuttallia decapetala Raf. (=Mentzelia decapetala (Raf.) Urb. & Gilg.
syn. Torreya Eaton, Man. Bot.(ed.5): 420- 421 (1826), nomen rejicendum (non Torreya Arn., Taxaceae 1838, nom. cons.).- Type species: Torreya ornata (Pursh ex Sims) Eaton (=Mentzelia ornata (Pursh ex Sims) Torr. & Gray) nomen illegitimum.
syn. Acrolasia K.Presl, Reliq. Haenkianae 2: 39 (1835) - Type species: Acrolasia bartonioides K.Presl
syn. Creolobus Lilja, Fl. öfver. Sver. odl. Vext.: 67 (1839) - Type species: Creolobus aureus Lilja (Basionym: Bartonia aurea Lindl., nomen illegitimum = Mentzelia lindleyi Torr. & Gray)
syn. Chrysostoma Lilja, Fl. öfver Sver. odl. Vext. Suppl. 1: 33 (1840), nomen illegitimum (homotypic with Creolobus Lilja)
syn. Touterea Eaton & Wright. N. Am. Bot. Ed. 8: 454. (1840), nomen nudum.
syn. Trachyphytum Nutt. ex Torrey & Gray, Fl. N. Am. 1: 533 (1840), nomen nudum.
syn. Hesperaster Cockerell, Torreya 1: 142(1901), nomen illegitimum (homotypic with Nuttallia Raf.)
syn. Bicuspidaria Rydb., Bull. Torrey Bot. Club 30: 275 (1903). - Type species: Bicuspidaria tricuspis (A.Gray) Rydb.
References: Darlington 1934; Hill 1976; Turner & Hempel 1995; Thompson 1963; Thompson & Lewis 1955; Thompson & Roberts 1971; Thompson & Powell 1981; Weigend & Rodriguez 1998.

 Annual or perennial herbs, subshrubs, shrubs or small trees; stinging hairs always absent. Leaves opposite, or opposite below and alternate above, sessile or petiolate, lamina ovate to triangular-ovate, occasionally lyrate, usually lobed, margin serrate or mucronate. Flowers in terminal, basitonic thyrsoids, each flower subtended by two bracts, sometimes flower and one bract shortly concaulescent with one of its axillary products; flowers erect, 5-merous, petals ovate to subcircular, membranaceous, planar, apex usually apiculate, white, yellow, or orange; stamens 10-200, equal to very unequal in length (sometimes outer ones twice as long as inner ones) or filaments of outer stamens dilated (petaloid), sometimes staminodial and equal in size and structure to the petals (M. decapetala); stigma punctate, placentae simple; capsule inferior, cylindrical to conical, sessile or pedicellate, chartaceous to lignescent, opening with 3-7 apical valves, seeds generally angular, testa striate or polyherdal, sometimes with central papillae, narrowly winged or smooth. 2n= 9, 10, 11, 14, 18, 27, 36 (Hill 1976).

Ca. 80 spp., Chile and Argentina to Canada, incl. Caribbean and Galapagos Islands, the vast majority of species in northern Central America and the southwestern USA. Most species are from desert and semi-desert habitats, some penetrate into grasslands and rain-green forests. This is currently the most poorly understood genus of Loasaceae as far as species limits are concerned. There are some fairly obvious larger groups, but within sections such as Trachyphytum and Mentzelia (M. hispida-group) taxon delimitation is extremely difficult.
 
 

Del. hort. Monac. 1844/4: 28. 1844. - Type species: Eucnide bartonioides Zucc., Del. hort. Monac. 1844/4: 28. 1844.
syn. Sympetaleia A.Gray, Proc. Amer. Acad. 12: 161. 1877. – Type species: Sympetaleia aurea A.Gray º Eucnide aurea (A.Gray) Thompson & Ernst
syn. Loasella Baillon, Bull. Soc. Linn. Paris 1: 650. 1887. – Type species: Loasella rupestris Baillon º Eucnide rupestris (Baill.) Thompson & Ernst
syn. Microsperma W.J.Hook., Ic. Pl. 3: Tab. 234. 1840. nomen illegitimum - Type species: Microsperma lobata W.J.Hook. º Eucnide lobata (W.J.Hook.) A.Gray
Reference: Thompson & Ernst 1967; Hufford 1987, 1988a, b; Weigend 1997c: 216.

Annual or perennial herbs; stinging hairs usually present. Leaves opposite below and alternate above, petiolate, lamina widely ovate to subcircular, margin shallowly lobed and deeply serrate or mucronate; flowers in terminal thyrsoids (sometimes with long, terminal monochasia) or simple dichasia, bracts 2 per flower, recaulescent; flowers erect, 5-merous, petals narrowly ovate or ovate, sometimes post- or congenitally united (sympetalous), membranaceous, planar, apex acute or rounded, green, white, yellow, or orange; stamens 10-200, filaments free to base or stamens epipetalous, equal, staminodes absent; stigma capitate, of 3-5 divergent lobes, placentae simple; capsule inferior, cylindrical to conical, pedicellate, pedicel sometimes strongly elongating after anthesis (chasmocarpous), chartaceous, opening with 3-5 apical valves, seeds striate. n=21 (Thompson & Ernst 1967)

12 spp., Guatemala to SW USA, most speciose in Mexico. The genus Eucnide was reestablished in its present form in an excellent study by Thompson & Ernst (1967) and now includes the sympetalous ‘genus’ Sympetaleia. Their conclusions have recently been confirmed with molecular techniques.
 
 

Contr. Gray Herb. Nat. Hist. N.S. 53: 61. 1918. - Type species: Schismocarpus pachypus Blake, Contr. Gray Herb. Nat. Hist. N.S. 53: 61. 1918.
Reference: Hufford 1989a.

Subshrub with annual shoots arising from an underground xylopodium; stinging hairs always absent. Leaves alternate, petiolate, lamina widely ovate to subcircular, entire, margin serrate; flowers in terminal thyrsoids, typically with one distal dichasium and one additional monochasial paraclade, bracts probably 2 per flower (1 in Hufford 1989a: Fig. 1), recaulescent; flowers erect, 5-merous, petals narrowly ovate or ovate, membranaceous, planar, apex acute, yellowish white; obdiplostemonous, stamens 10, 5 shorter, 5 longer, staminodes absent; stigma capitate, of 5 divergent lobes, placentae simple; capsule semisuperior, ovoidal, pedicellate, chartaceous, opening with 5 apical valves, seeds striate.

1 species, Mexico, only Oaxacá. Another species has been described from the same area (Schismocarpus matudai Steyerm.), but that is probably conspecific with S. pachypus. The genus is still poorly understood as no meaningful comparison with other Loasaceae has been carried out.
 
 

Ench. Bot.: 493. 1841. - Basionym: Gronovieae Rchb., Handb. Nat. Pfl. Syst.: 232. 1837. - Type genus: Gronovia L.
syn. Cevalliaceae Grisebach, Grundriss der syst. Bot.: 136. 1854. - Type: Cevallia Lagasca

Winding annual or perennial herbs or lignescent lianas or shrubs or subshrubs, 40 -300 cm tall. Stems terete, bark, if present, smooth or thickly covered with cork layers. Indument very variable but always including glochidiate or scabrid trichomes of some sort, often additionally with urticant setae or splinter hairs. Leaves always alternate, linear to suborbicular, entire or variously divided, lobed, subpalmately divided, margin usually lobulate or rarely entire; exstipulate. Inflorescences terminal, thyrsoids or racemes, sometimes condensed and subcapitate, bracts linear or leafy. Flowers bisexual, usually proterandric. Calyx tube ovoidal, usually pentagonous in transverse section, often winged, very densely covered with trichomes, calyx lobes 5, linear to linear-lanceolate, green, white or bright yellow, persistent or caducous, usually accrescent after anthesis. Petals 5, free or rarely laterally fused, apert, sometimes reduced, spatulate, plane, entire or laciniate, thinly membranaceous, white or pale yellow. Staminodia absent or 2 - 3 stamens staminodial, reduced to the filaments. Stamens 5, episepalous, filaments filiform, sometimes very short. Anthers oblong, linear or globose, laterally dehiscent, bilocular, connective undifferentiated or conspicuously protracted beyond anthers. Ovary inferior, unilocular, with 1 pendent ovule; disc anular, cup-shaped, free apex of ovary later sclerified and frequently hispid (sometimes with urticant setae). Style simple, filiform, stigma dome-shaped 3- to 5-cleft.
Fruit a cypsela crowned with the persistent calyx lobes and with a sligthly sclerified wall or seed enclosed in bract and bracteoles and calyx lobes caducous. Seed without differentiated, dark testa, endosperm oily, embryo straight.

Gronovioideae sensu Urb. & Gilg (i.e. in Loasaceae) have always been considered as marginal to Loasaceae and it seems best to remove this haplostemonous, uni-ovulate group from the family altogether. Gronoviaceae are probably the sister group to Loasaceae and any search for affinities for the group should probably take Gronoviaceae into consideration: They appear to have retained a proportionally higher number of ancestral character states. Good molecular data are, unfortunately, still missing for the delimitation of Gronoviaceae and Loasaceae. Gronoviaceae Endl. readily fall into two different groups, closely related though highly differentiated genera Gronovia, Cevallia and Fuertesia (subfam. Gronoviaceae) on the one hand and the genus Petalonyx (subfam. Petalonychoideae) on the other. The genera are centered in northern Central America with Gronovia reaching into South America, Fuertesia endemic to Hispaniola and Cevallia and Petalonyx reaching into the sw US.
 
 

Denkschr. Reg. Bot. Ges. 3: 200. - Type genus: Gronovia L.
Genera: Gronovia, Fuertesia, Cevallia.
References: Poston & Nowicke 1993.

Lianas, annual vines or subshrubs, stinging hairs or splinter hairs sometimes present, bark never with conspicuous cork-layers. Inflorescences terminal thyrsoids, usually with a terminal dichasium and one or two additional paracladia. Sepals free to base or united; petals entire or laciniate, staminodia absent, anthers bifacial, laterally dehiscent, connective undifferentiated or conspicuously protracted beyond anthers. Fruit a cypsela crowned with the persistent calyx lobes, free from its bracts and bracteoles, and with a slightly sclerified wall.

In spite of the superficial differences of Cevallia and Gronovia, it can be easily shown that some crucial characters are very well matched between these two taxa: The apparently capitate inflorescence of Cevallia can be derived from the more obvious thyrsoid of Gronovia by a simple shortening of the internodes.
 
 

Sp. pl. 1: 202. - Type species: G. scandens L.

 Scandent, annual herbs, stinging hairs and characteristical glochidiate hairs 0.5 mm long with two hooks at their tip always present. Leaves opposite below, alternate above; lamina reniform, deeply sinuate-lobate with 3-4 lobes on each side, lobes ovate-lanceolate, long acuminate, membranaceous, margins entire. Flowers in terminal thyrsoids, typically with distal dichasium and one additional, monochasial paraclade, flowers 5-merous, subsessile, with 2 linear bracts per flower, calyx lobes free or united nearly to apex, yellow or yellowish green; petals entire, reduced or long and shortly exserted from the calyx, thinly membranaceous, pale yellow; stamens episepalous, anthers bifacial, connective not differentiated, staminodia absent; fruit an ovoidal cypsela, pentagonous in cross section, alate on the ribs, crowned with persistent calyx. n= 37 (Davis & Thompson 1967)

2 spp., N. Peru to Mexico. Gronovias are fast-growing weeds in raingreen forests, G. longiflora is endemic to S. Mexico and G. scandens is widespread.
 
 

Ber. D. Bot. Ges. 28: 515. 1910. - Type species: F. domingensis Urb.

Liana, splinter hairs and characteristical glochidiate hairs 0.5 mm long with two hooks at their tip always present. Leaves alternate; lamina cordate, coriaceous, margin entire. Flowers in terminal thyrsoids, typically with distal dichasium and 1-3 additional, dichasial paraclades, flowers 5-merous, subsessile, with 2 linear bracts per flower, calyx lobes free, yellowish green; petals laciniate, included in the calyx, thinly membranaceous, pale yellow; stamens episepalous, anthers bifacial, connective not differentiated, staminodia absent; fruit an ovoidal cypsela, pentagonous in cross section, alate on the ribs, crowned with persistent calyx.

Monotypical, Hispaniola. This taxon was discovered in 1910 and has since been frequently recollected. It is essentially a perennating, more drought-resistant version of Gronovia, its undoubted closest ally.
 
 

Gen. sp. pl.: 35. - Monotypical: C. sinuata Lagasc.
syn. Petalanthera Nutt., J. Ac. Phil. 7(1): 107. 1834. – Monotypical: Petalanthera hispida Nutt. = C. sinuata Lagasc.
Reference: Davis & Thompson 1967

Subshrub, arbuscular hairs always present, stinging hairs absent. Leaves alternate; lamina narrowly ovate, margin sinuate. Flowers in terminal thyrsoids, typically with distal dichasium and 1 additional, mono- or paraclade, strongly condensed to resemble a capitate inflorescence; flowers 5-merous, subsessile, with 2 linear bracts per flower, calyx lobes and petals identical, free to base, whitish, membranaceous; stamens episepalous, anthers bifacial, connective long protracted into club-shaped appendage, staminodia absent; fruit an ovoidal cypsela, pentagonous in cross section, crowned with persistent calyx. n= 13 (Davis & Thompson 1967).

Monotypical, SW USA and N Mexico.
 
 

Nasa and the Conquest of South America: 217. 1997. subfam. nov. – Monogeneric: Petalonyx A.Gray
Reference: Davis & Thompson 1967, Hufford 1989b.

Shrubs and subshrubs, often from a thickened, perennial rootstock, bark often with thick cork-layers. Inflorescences terminal racemes; petals free to base or postgenitally fused, often clawed, white; filiform staminodia sometimes present, stamens 5, episepalous, sometimes displaced outside the pseudosympetalous corolla or filaments locked between the petal margins, unifacial, connective undifferentiated. Fruit a cypsela which remains attached to bract and the pairs of bracteoles, calyx deciduous. n= 23 (Davis & Thompson 1967).

One genus with the characters of the subfamily. This genus is very distinctive with regards to flower, fruit and inflorescence morphology. Its racemose inflorescence can not be meaningfully compared to that of other Loasaceae (e.g. Eucnide: Hufford 1989b).
 
 

Pl. nov. thurb.: 319. 1854. - Type species: Petalonyx thurberi A.Gray.
Reference: Davis & Thompson 1967.

 5 spp., 2 spp. in Mexico, 3 spp. in SW USA. Deserticolous shrubs and subshrubs.
 
 
 
 

Introduction

Key to the genera

Familial and Generic Classification

Infrageneric entities

Species

Index of Pictures

Literature