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(Last Modified On 1/10/2013)
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(Last Modified On 1/10/2013)
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Family
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MELASTOMATACEAE
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Contributor
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H. A. GLEASON
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Description
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Flowers regular, perigynous or epigynous, usually 4- to 6-merous. Hypan- thium cylindric to saucer-shaped, bearing the sepals, petals and stamens on a terminal torus. Calyx usually small, in most genera open in the bud, in some genera calyptrate. Petals distinct, large or small, usually white to pink or purple, rarely red or yellow, convolute in the bud. Stamens commonly twice as many as the petals, rarely more numerous, rarely fewer by abortion, isomorphic or dimorphic. Anthers basifixed, ovoid to subulate, 2-celled or 4-celled, opening by one (rarely two) terminal pores or in a few genera by short sub-terminal slits; connective often prolonged below the thecae or below the insertion of the filament into one or more lobes, spurs or appendages of various types. Ovary 1, 2- to several-celled, superior or inferior, commonly many-ovuled; style 1; stigma 1, punctiform to capitate. Fruit a loculicidal capsule more or less enclosed by the persistant hypanthium if from a superior ovary, or a berry if from an inferior ovary. Trees, shrubs, herbs or vines; leaves simple, opposite, often unequal, occasionally apparently alternate by abortion of one member of each pair, entire or toothed, usually 3- to several-nerved (1-nerved in Mouriri and a few species of other genera). Inflorescence always cymose, axillary or terminal, or flowers solitary.
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Distribution
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About 200 genera and 4000 species, almost entirely tropical and most numer- ous in South America.
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Key
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a. Fruit a loculicidal capsule; ovary superior, free from the hypanthium. b. Connective of the anthers bearing one or more dorsal spurs or append- ages. c. Flowers (in our species) 5- to 6-merous; seeds linear or cuneiform. (Tribe MERIANEAE.) d. Calyx open in the bud, exposing the corolla. e. Climbing vines; leaves subrotund; pubescence of Malpighian hairs; seeds linear, winged at both ends, the embryo near the center1.............................................. 1 . ADELOBOTRYS. ee. Trees; leaves ovate to oblong or elliptic; pubescence none or not Malpighian; seeds narrowly cuneiform, not winged, the embryo at the base. f. Basal spur of the connective sharp or conic .... 2. MERIANIA. ff. Basal spur of the connective inflated, rounded ......................... 3. AXINAEA. dd. Calyx calyptrate in the bud, at anthesis deciduous at or near the torus. e. Petals obovate or rounded, in our species about 18 mm. long. 4. CENTRONIA. ee. Petals lanceolate to ovate, acuminate, in our species up to 7 mm. long .--- 5. CALYPTRELLA. cc. Flowers 4-merous; seeds short, cochleate. (Tribe RHEXIEAE.) ........ 6. MONOCHAETUM. bb. Connective of the anthers with ventral lobes, spurs, or appendages, or rarely nearly simple. c. Capsule in cross-section round, sulcate or prismatic, or obscurely angled; flowers very rarely spicate. d. Seeds not cochleate; fertile anthers 5 or leaves strongly di- morphic. (Tribe MICROLICIEAE.) e. Fertile anthers 5, each tipped by a sterile beak; leaves essentially ssom orphic ....................................................................................... 7. R HYNCHANTHERA. ee. Fertile anthers 8; leaves strongly dimorphic - -.-.-.-..-.-.8. CENTRADENIA. dd. Seeds cochleate; stamens all fertile; leaves essentially isomorphic. (Tribe TIBOUCHINEAE.) e. Hairs of the upper leaf-surface (if present) not adnate to the epidermis for a portion of their length; ovary not setose at the summit (except in Schwackaea). f. Connective of the outer series of stamens bearing at its base a single ventral appendage which is 2- to 3-toothed or 2- 3-setose at its apex. --------------...-.-----..----------------------9. ARTHROSTEMA. ff. Connective of the outer series of stamens more or less evi- dently 2-lobed at base, or rarely (Aciotis) nearly simple. g. Stamens strongly dimorphic, the connective of the outer series, between the base of the thecae and the summit of the filament, several times as long as that of the inner series. h. Hypanthium wingless, campanulate to subglobose..... 10. HETEROCENTRUM. hh. Hypanthium narrowly 8-winged, nearly cylindric. -------- 11. SCHWACKAEA. gg. Stamens weakly dimorphic, usually differing somewhat sn ssze. h. Petals acute or acsrminate. i. Connective prolonged at base into two conspicuous ascending spurs .............................................. 12. NEPSERA. ii. Connective simple at base, or with two very short rounded lobes ..................................1...... ....... .. 13. ACIOTIS. hh. Petals obtuse or rounded .-... 14. ACISANTHERA. ee. Hairs or scales of the upper leaf-surface adnate to the epidermis for a portion of their length; ovary setose at the summit. f. Hypanthium hirsute with stout hairs from a branched basc; hairs of the stem mostly geniculate at base; flowers 4-merosis. 15. PTEROLEPIS. ff. Hypanthium pubescent with simple or glandular hairs or scales or nearly glabrous; flowers 4-merous or (in all common species) 5-merous.- . 16. TsIoucHINA. cc. Capsule in cross-section very strongly 3-winged, its distal margin much prolonged beyond the deeply concave summit; flowers sessile in dense secund spikes. (Tribe BERTOLONIEAE.) d. Connective of the anther with a single ventral spur; herbs with basal leaves- - 17. MONOLENA. dd. Connective with 2 or 3 basal spurs; leaves cauline. e. Basal spurs of the connective 2; leaves commonly distinctly dimorphic.-.----..--------------------.18. DIOLENA. ee. Basal spurs of the anther 3; leaves commonly isomorphic.. 19. TRIOLENA. aa. Fruit a berry; ovary wholly or partly inferior. b. Anthers opening by a terminal or nearly terminal pore or pores (or in one species by a longitudinal ventral cleft in each theca), minutely or not at all glandular; leaves in all our species with 3 or more primary nerves. c. Flowers individually subtended by two pairs of decussate bracts inserted at the base of the hypanthium; anthers coherent in a ring, each theca opening by a separate pore. (Tribe BLAKEAE.) (204) This content downloaded by the authorized user from 192.168.82.203 on Tue, 27 Nov 2012 17:44:06 PMAll use subject to JSTOR Terms and ConditionsI958] FLORA OF PANAMA (Melastomataceae) 205 d. Anthers short, oval, oblong, or elliptic, blunt or broadly rounded at the summit. ------------------------------------------------- 20. BLAKEA. dd. Anthers linear to lanceolate or subulate .------------------------------- 21. TOPOBEA. cc. Flowers not individually subtended by decussate bracts; anthers separate at anthesis, in most species opening by a single pore. (Tribe MICONIEAE.) d. Flowers lateral or axillary, solitary or cymose at the nodes of the stem. e. Petals obtuse or rounded. f. Anthers linear to oblong or subulate, opening by a single pore. (But see also Clidemia pitsieri, with dimorphic, sessile, cordate-clasping leaves.) g. Flowers or flower-clusters from the axils of existing leaves. 22. CLIDEMIA. gg. Flowers from leafless nodes below the existing leaves. - 23. HENRIETTEA. ff. Anthers broadly oblong or dolabriform, more or less coherent in a ring. g. Anthers opening by two minute terminal pores ................... 24. BELLUCIA. gg. Anthers opening by a single pore 25. LOREYA. ee. Petals acute or acuminate. f. Flowers arising from leafless nodes below the existing leaves. 26. HENRIETTELLA. ff. Flowers or flower-clusters arising from the axils of existing leaves .-27. OSSAEA. dd. Flowers in terminal inflorescences. e. Petals acute or acuminate ------------------------------------ ------------------------ 2 8. LEANDRA. ee. Petals obtuse, rounded or retuse. f. Calyx calyptrate in bud, deciduous at the torus at anthesis. 29. CONOSTEGIA. ff. Calyx open in the bud, its lobes persistent at anthesis, but often minute. g. Formicaria present at the summit of the petioles of the larger leaves - ...-- ....................--....--..........30. TOCOCA. gg. Formicaria none. h. Younger stems and petioles (in the Panama species) at once stellate-tomentose, glandular-hirsute, and simply hirsute ........................-..........-............... .. 31. HETEROTRICHUM. hh. Pubescence never of three types at once ........- - 32. MICON}A. bb. Anthers opening by two lateral slits, one on each side; connective bearing a large gland on the back near the middle of the anther; leaves (in our species) 1-nerved. (Tribe MEMECYLEAE.) -------------------- 3 3. Mouriri.
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