Brachyotum sanguinolentum (Naudin) Triana
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Authority
Wurdack, John J. 1953. A revision of the genus Brachyotum (Tibouchineae-Melastomataceae). Mem. New York Bot. Gard. 8 (4): 343-407.
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Family
Melastomataceae
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Scientific Name
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Description
Species Description - Trichomes smooth. Branchlets notably quadrangular, nearly glabrous to moderately short-strigose or the pubescence spreading. Petiole 2-18 mm. Blade 17-76 x 9-25 mm., elliptic with the apex acute to rounded-acute or obtuse and the base acute to obtuse, the 3 primaries (occasionally an additional pair of marginals varyingly developed) and 15-30 pairs of secondaries obscurely to noticeably (but narrowly) impressed above and finely elevated below, the secondaries usually reticulate; above glabrous or very sparsely strigulose to moderately short-strigose, the hairs to 7/mm.2 with their basal 1/4-1/2 adherent; below nearly glabrous to moderately loose-short-strigose or hirsutulous, the hairs to 15/mm.2, the glands usually solitary and 6-20/mm.2 but occasionally in clumps. Flowers constantly 4-merous, in terminal corymbiform usually ternate few- to many-flowered cymes, the cymes unbranched to twice-branched below the cymes, the ultimate pedicels solitary to ternately dichasial. Pedicel 0-10 x 0.4-0.5 mm. below the bracteoles, 3-9 x 1-1.2 mmt above, often ebracteolate in the more crowded and floriferous cymes; peduncular bracts and pedicellar bracteoles very early caducous, grading in size from peduncular bracts 7 x 2 mm. or smaller to pedicellar bracteoles 0.7 x 0.15 mm., glabrous except for sparse short appressed marginal and abaxial-midvein hairs. Hypanthium 3.5—5 x 3-4 mm., 0.1-0.3 mm. thick medianly, nearly glabrous to very sparsely strigulose or loosely and sparsely short-strigose. Sepals 2-3.5 x 2.5-4 mm., broadly triangular and tipped with a short acumen, united at bases 0.8-1.5 mm., the sinuses obtuse. Petals deep purple, 10-15 x 6-11 mm., obovate with the apices broadly and asymmetrically obtuse, the cilia 0.1-0.3 mm. and non-glandular or with early-caducous glandular tips. Filaments 3-5.5 mm.; anthers 3-5 mm.; connective at anther base (0.6-)0.8-1.1 mm., free of the anther 0.3-0.4 mm., the ventral lobing 0.1-0.4 mm. Style 15-24 x 0.4-0.5 mm., exserted 4-7 mm. Ovary 4-5 x 2.5-3 mm., sparsely to moderately strigulose on the apical 1-2.5 mm., the apical lobes 0.5-1 mm. above the locules.
Distribution and Ecology - Distribution: southeastern Peru to northeastern Bolivia, alt. 2300-3500 m.
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Discussion
Chaetogastra sanguinolenta Naudin, Ann. Sci. Nat. III. 14: 131. 1850.
Brachyotum floribundum (Grisebach) Triana, Trans. Linn. Soc. 28: 49. 1871. Nomen.
Brachyotum floribundum (Grisebach) Triana ex Cogniaux; DC. Monog. Phan. 7: 155. 1891.
Brachyotum barbiferum Rusby, Phytologia 1: 69. 1934.
Brachyotum pedicellatum Markgraf, Notizbl. Bot. Gart. Berlin 13: 460. 1937.
Type Collection and Locality: Weddell 4605 (HOLOTYPE P); Bolivia, Dept. La Paz, "prov. de Larecaja et Caupolican (vallees entre Tipoani et Apolobamba) Mai 1847.. .a 2500 metres" (fide holotype).
Type Photographs: Gleason 51-3 (type no. of B. floribundum, in G-DC ?); F16709 (destroyed isotype of B. floribundum at B); New York s.n. (holotype of B. barbiferum).
Vernacular Names: Tili-tili (Vargas 9708).
Several sheets of Lechler 1857 (G-BOIS, K, W) were annotated by Triana, but, of these, only the Geneva specimen had been annotated by Cogniaux also; the Gleason type photograph shows still another sheet annotated by both Triana and Cogniaux. The locality of the Pearce collection (Huaycani, or Huagcani ?, or Huagcaui ?, or Huaycaui ?) could be any of several localities in northeastern Bolivia with slightly different spellings. Other parts of Mandon 640 include B. grisebachii and Tibouchina latifolia (Naud.) Britton; a portion of Vargas 9708 is B. grisebachii.
All the cited collections are certainly conspecific. "Typical" B. sanguinolentum has young branchlets nearly glabrous except for the short nodal setae; petioles 2-5 mm.; blades 18-33 x 9-13 mm., above very sparsely strigulose (the hairs less than 1/mm.2) to glabrous, below very sparsely strigulose along the primaries but nearly or quite glabrous on the secondaries and surface; and the hypanthium glabrous or nearly so, the hairs less than 1/mm.2 This element includes Weddell 4605, Mandon 640 p.p., Tate 861, and Bang 2860; Markgraf's description of B. pedicellatum differs in no respect from these specimens. Aside from Weberbauer 626 and Pearce s.n., the remainder of the specimens cited under B. sanguinolentum have young branchlets sparsely to moderately strigulose or short-strigose; petioles 3-18 mm.; blades (17-)30-76 x (6-)15-25 mm., above sparsely strigulose to moderately short-strigose (2-7/mm.2), below sparsely to moderately strigulose or loose-short-strigose along the primaries and sparsely strigulose on the surface (2-14/mm.2); and the hypanthium sparsely strigulose (2-12/mm.2). These specimens would correspond to B. floribundum, including B. barbiferum. Pearce s.n. has the large leaves of this latter group, the vegetative pubescence density of the "sanguinolentum" element, and hypanthial pubescence density of 2/mm.2 Weberbauer 626 has the branchlet, peduncle, and pedicel pubescence spreading, the blade apices often rounded, and the lower leaf surface pubescence denser than in the "floribundum" element, but otherwise agrees in leaf size and pubescence density with that element. Such variation in degree of appression of pubescence has been noted in other species (B. grisebachii, B. rostratum) where intermediate degrees were fully represented, and does not seem worthy of formal recognition. Cogniaux's limited citations of dimensions suggest an inverse quantitative correlation between leaf and flower size, but such a relation does not exist. Successful infraspecific differentiation based on leaf size and pubescence density seemms probable, but has been deferred.