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MONOTROPA Linnaeus, Sp. pl. 1: 387. 1753. -- Lectotype:  Monotropa uniflora Linnaeus.
 

[Hypopitys J. Hill, Brit. herb. 221. 1756, nom. illeg.  Hypopithys Scopoli, Fl. carniol. ed. 2, vol. 1: 285.  1771, nom. illeg. (orthographic variant).  Hypopithis Rafinesque, Medical Repository of New York, ser. 3, 1: 297.  1810, nom. illeg. (orthographic variant).]

Monotropion Saint-Lager, Ann. Soc. Bot. de Lyon 7: 130. 1880.

     Plants without chlorophyll, mycotrophic, to 30 cm tall.  Roots shallow, forming an open system along which are often found more dense clumps of branched roots;  ultimate branch segments usually free for a short distance. Inflorescences nodding, racemose or reduced to a solitary flower;  bracts present, sometimes similar to perianth;  bracteoles present in some specimens of M. hypopitys.  Flowers nodding at anthesis, becoming erect in fruit, more or less fleshy, (3-) 4-5 (-6)-merous;  calyx similar to corolla, quite distinct or apparently absent, similar or not in color to corolla, glabrous or sparsely glandular pubescent, color ranging from white to yellowish, orange or pink shades;  corolla cylindrical, or slightly flared distally, polypetalous, imbricate in bud, petals saccate at base, often pubescent on inner surface, apices acute to truncate, color ranging from white to yellowish, orange or pink shades;  stamens 8-10, generally twice as many as corolla lobes, in two series of alternating lengths, included, color similar to corolla, no appendages;  anthers with connate sacs in a horizontal plane or erect and hippocrepiform, smooth, lacking appendages or rarely awned, and disintegration tissue, dehiscence terminal;  pollen lacking viscin threads, shed singly;  ovary superior, usually pubescent, 5 (4-6) locular, placentation axile;  nectary present as 8-10 lobes projecting basipetally from between staminal bases, paired opposite the saccate bases of the petals;  style cylindric, slender or stout, elongate or short, included, conspicuously articulated with ovary;  stigma umbilicate to deeply funnelform, with 4-6 shallow lobes, glabrous or with a dense ring of subtending hairs.  Fruit a loculicidal capsule, opening from apex to base, pedicels erect at maturity, capsular segments persistent or irregularly deciduous, vascular bundles between separated capsular segments may persist in fruit linked by several lateral smaller vascular bundles;  seeds spindle-shaped, minute, 0.5-1 mm long, light brownish;  embryo two-celled.  Chromosome numbers: n=24 or 2n=32; M. hypopitys 2n=ca. 48.

Key to Neotropical Species                                                                                               Back to Top

1.  Inflorescences with several flowers, rarely reduced to a single flower; sepals distinct
     from petals;  petals narrowly saccate at base;  anthers hippocrepiform, erect at
     anthesis, dehiscence by a single terminal slit;  stigma only slightly funnelform, often
     subtended by ring of stiff hairs;  style slender;  lobes of nectary short and stout;
     capsular segments thin, often deciduous late in season;  inflorescences ranging from
     light yellow to reddish at anthesis, drying brownish (Mexico, Guatemala)....... M. hypopitys.
1.  Inflorescences never more than a single flower;  sepals often similar to petals;
     petals broadly saccate at base;  anthers not hippocrepiform, horizontal at anthesis,
     dehiscence by slit open at its ends or along its length;  stigma conspicuously
     funnelform, not subtended by a ring of stiff hairs;  style stout;  lobes of nectary
     elongate and slender;  capsular segments thick, often persisting until following season;
     inflorescence ranging from white to orange-red or combinations of these, drying black
     (Mexico to C. Colombia)..............................................................................  M. uniflora.

     This is a version of the taxonomic treatment of the neotropical species of Monotropa (Ericaceae) by Gary D. Wallace, 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: 13-27 (Wallace, 1995b).  This is published with permission of The New York Botanical Garden and Gary D. Wallace.

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