James L. Luteyn and Paola Pedraza-Peñalosa
The New York Botanical Garden
|
|
Pernettya Gaudichaud (Ericaceae: Vaccinioideae: Andromedieae) is a genus of 14 species of small, strictly terrestrial shrubs to subshrubs. It is distributed throughout the cordilleras from north-central Mexico to Tierra del Fuego with outlying populations in the Guayana Highlands, Galápagos and Juan Fernández Islands, and in Tasmania and New Zealand. It is characterized by usually small leaves, inflorescences with usually solitary flowers, anthers with awns, superior ovary, and fruit a berry. The calyx is persistent in fruit and subtends the berry, normally remaining membranaceous, but sometimes the calyx lobes become totally or only proximally fleshy. They do not, however, become accrescent nor do they surround the fruit at maturity as in Gaultheria. They have branched, rhizome or stolon systems and the plants survive fire through bud sprouting from these rhizomes (Laegaard, 1992). |
Pernettya
prostrata is self-compatible and sets viable seed without flower visitors
in the greenhouse. Sleumer (1952, 1985) reported dioecism for P.
howellii. Gynodioecism has been reported for P. prostrata (called Gaultheria myrsinoides) from Ecuador (Middleton, 1991a).
Middleton (1991a) also reported pollen inviability ranging from 0 to 70%
in P. prostrata in Ecuador and empty anthers in what appeared to
be normal flowers and anthers. Intergeneric hybridization between Pernettya and Gaultheria (=xGaulnettya) are well known
in the gardening trade. In addition, Middleton (1989, 1990, 1991a)
and Luteyn (1995d) discussed natural hybridization in the Neotropics.
Sleumer (1985) mentioned the possibility of infraspecific hybridization
in temperate South American species and Baas (1985) stated that "Hybridisation
is apparently a common phenomenon in Pernettya, not only between
species of Pernettya, but also with species of the related genus Gaultheria." Luteyn (1995d), however, saw no evidence of this
in the herbarium or in the field, and because of the seeming close relationship
between the species based on morphological evidence, stated that he would
not be surprised if they are interfertile. The greatest use for Pernettya today is probably as a cultivated plant in European rock gardens.
There are mixed reports as to the edible nature of the fruits of Pernettya in their natural habitats, ranging from fruits sweet and edible to claims
of intoxication (the Peruvian vernacular name "macha-macha" means drunkenness;
cf. Macbride, 1959 and Sleumer, 1985) or hallucination after eating (Luteyn,
1995d).
There is no dispute that Pernettya and Gaultheria are more closely related to each other than to other
genera. The traditional and current difference between the two genera
is that Pernettya has a baccate fruit and Gaultheria a capsule.
Usually the berry of Pernettya is subtended by a dry calyx, while
the capsule of Gaultheria is enclosed by a fleshy calyx. Intermediate
states (almost exclusively with regards to the condition of the calyx)
have been noted. Middleton and Wilcock (1990a), presenting a number
of examples from the literature as well as their own studies in an attempt
to clarify the taxonomic status of Pernettya, concluded that "Pernettya should not be maintained as a separate genus from Gaultheria, the
only character which separates them being the fruit which even then is
not completely discontiuous." Luteyn (1995d), however, continued
to maintain Pernettya as distinct from Gaultheria in agreement
with Sleumer (1935b, 1985), stating that many of the supporting characters
(and/or character states) used by Middleton and Wilcock to refute the distinction
of two genera did not hold up under closer scrutiny, there being too many
overlapping or nonexclusive features. He concluded that the fruit
difference (i.e., berry in Pernettya and capsule in Gaultheria)
was sufficient to recognize two genera.
Pernettya was revised in its entirety
by Sleumer in 1935b; then in 1985 he gave a detailed, up-dated review
of the genus but did not include discussions of relationships or the citation
of specimens. Middleton (1989, 1990, 1991b) united the genus under Gaultheria. Luteyn (1995d) revised the neotropical members
of the genus based on extensive field work from throughout their range
and all available literature and type specimens.
PERNETTYA Gaudichaud in Mirbel, Ann. Sci. Nat. (Paris)
5: 102. 1825 (as Pernettia); orth. corr. Gaudichaud
in Freycinet, Voy. Uranie Bot. 454, t. 67. 1829, nom. & orth.
conserv. versus Pernettia Scopoli 1777 (Campanulaceae). Type
species: Pernettya pumila (Linnaeus f.) Hooker. Dedicated
to M. Pernetty, author of a history of his voyage to the Falkland Islands
(Don, 1834).
Hippomanica Molina, Sag. Stor. Nat. Chili 126, 351. 1782; ed. 2: 140, 288. 1810. Type species: Hippomanica insana Molina.
Repent, procumbent, or erect shrubs, rarely
cushion plants, bisexual or by abortion of pollen or ovules unisexual,
then dioecious or gynodioecious; stems puberulous with simple, unicellular
hairs (glabrous), and usually also moderately to densely strigose or setose
with basally swollen, ferruginous, multicellular, multiseriate, straight
or crisped (glandular-tipped hairs). Leaves alternate, evergreen,
coriaceous, pinnately veined, apex obtuse or midrib protracted into an
achlorophyllous mucro, margin entire or often subserrate-crenulate, the
teeth then bristle-tipped with short to long, multicellular, multiseriate,
eglandular or glandular-tipped hairs, glabrous (setose) beneath, short
petiolate. Inflorescence with flowers usually solitary in axils of
upper leaves (leaves reduced and congested, flowers then pseudo-racemose
or racemose only in P. insana in temperate S. America); pedicels
bracteate at base and with 2-many bracteoles along the length nearly to
apex, articulate beneath the calyx.
Flowers nodding; calyx persistent, 5-parted nearly to base, glabrous,
lobes ovate to elliptic, acute, often ciliate, normally membranaceous and
not accrescent in fruit (1-5 becoming succulent after anthesis, then remaining
at base of fruit, or accrescent to lower half of fruit in some southern
hemisphere, temperate species); corolla glabrous, tube urceolate,
cylindric to ovoid or subglobose, white or tinged with pink or rose, lobes
less than 1/10 as long as corolla tube, deltate, acute to obtuse, reflexed;
stamens (8-)10, about 1/2 as long as corolla, filaments slightly to conspicuously
dilated above the base, papillate, glabrous to pilose, anthers without
spurs, but distally 4-awned, awns 0.4-0.5 mm long (vestigial), with disintegration
tissue present dorsally at base of awns, thecae 0.8-1.5 mm long, dehiscing
at apex by terminal pores; ovary superior, 5-locular, glabrous to
densely short-pilose, style 2-3 mm long, glabrous. Berry subglobose
to globose, depressed at apex, dark blue-black (light purple to almost
white), glabrous to densely short-pubescent; seeds numerous, small,
angular, compressed, ca. 1.2 mm long; testa impressed-punctate.
Chromosome number: x=11.
Key to Neotropical Species Back to Top
1. Leaf apex distinctly mucronate.
2. Leaf midrib and margin not thickened,
margin often revolute, the mucro
persistent;
plants with thin-stemmed, slender habit; Galápagos Islands,
650-1040 m ................................................................................. P. howellii.
2. Leaf midrib and margin conspicuously
thickened, margin curled but not
revolute, mucro
not always persistent; plants with thick-stemmed, stout habit;
Costa Rica,
3300-3600 m ........................................................... P. prostrata.
1. Leaf apex obtuse or acute, not mucronate; mainland S
America, Central
America, and Mexico.
3. Corolla 7-9 mm long; multicellular
hairs on stems and pedicels gland-tipped;
filaments
glabrous or conspicuously pilose-ciliate; Guayana Highland ...........
.................................................................................................. P. marginata.
3. Corolla less than 7 mm long;
multicellular hairs on stems and pedicels
eglandular;
filaments glabrous, merely papillose; Mexico, Central America,
and Andean South
America.
4. Leaves
and stems densely long-hispid or setulose; leaves dark maroon
or purplish beneath; Colombia (Cundinamarca Dept.) .................... P. hirta.
4. Leaves
and stems glabrous to pubescent with strigose or weakly hirsute-
setulose hairs; leaves green beneath; Mexico, Central America,
and
Andean South America ............................................................ P. prostrata.
This is a version of the taxonomic treatment of the neotropical species of Pernettya by James L. Luteyn, modified from "Ericaceae--Part II. The Superior-Ovaried Genera (Monotropoideae, Pyroloideae, Rhododendroideae, and Vaccinioideae p.p.)." The full treatment including specimen citations may be see in Flora Neotropica Monograph 66: 365-383 (Luteyn, 1995d). This on-line synthesis is published with permission of The New York Botanical Garden.