Brachyotum alpinum Cogn.

Authority

Wurdack, John J. 1953. A revision of the genus Brachyotum (Tibouchineae-Melastomataceae). Mem. New York Bot. Gard. 8 (4): 343-407.

Family

Melastomataceae

Scientific Name

Brachyotum alpinum Cogn.

Description

Species Description - Trichomes smooth, slender. Branchlets quadrangular, sparsely strigulose, soon glabrescent. Petiole 1-4 mm. Blade (6-)10-17x 4-9 mm., the shape and venation as in B. lindenii; above glabrous to very sparsely strigulose, the hairs to 1-2/mm.2 and with their basal 1/3 adherent; below sparsely strigulose on the primaries, the surface glabrous to sparsely loose-strigulose, the hairs to 7/mm.2, the glands as in B. lindenii. Flowers constantly 4-merous, the inflorescences as in B. lindenii. Hypanthium 4-7 x 4-5 mm., 0.3-0.4 mm. thick medianly, sparsely strigulose, the- hairs 4-8/mm.2 Sepals 3.5-8 x 3-4 mm., lanceolate to oblong-lanceolate with acute apices, united at bases 0.5-1.2 mm., the sinuses acute to rounded-acute. Petals deep purple, 10-14x8-11 mm., asymmetrically obovate with the apices rounded to broadly obtuse, the eglandular cilia 0.1-0.6 mm. Filaments 4-4.5 mm.; anthers 4.5-6.5 mm.; connective at anther base 1-1.5 mm., free of the anther 0.4-0.8 mm., the ventral lobing 0.3-0.6 mm. Style 17-22 x 0.4-0.6 mm., exserted 3-6 mm. Ovary 4-5.5 x 2.5-3.5 mm., moderately strigulose on the apical 1.5-2.5 mm., the apical lobes 0.3-1 mm. above the locules.

Distribution and Ecology - Distribution: north central Ecuador, alt. 3200-4000 m.

Discussion

Type Collection and Locality: Jameson s.n. (or 193 ?) (SYNTYPES presumably in G-DC and LE; isosyntypes 3R, F, G-BOIS, G-DEL, K, US, W) and Fraser s.n. (SYNTYPE presumably in G-DC); Ecuador, Prov. Chiraborazo, "mont. Chimborazo altit. 4000 m.," and "Ecuador," respectively.

Type Photographs: Gleason 51-5 (Jameson and Fraser syntypes presumably in G-DC); F25862 (Fraser syntype presumably in G-DC).

No lectotype was selected since material was not seen of either of the syntypes which had been annotated by Cogniaux (except the specimen in the Cogniaux herbarium). Some of the Jameson sheets are unnumbered and some are numbered 193; also, without correlation, some have complete data on the place of collection (Chimborazo) and some are merely labeled "Quito"; these specimens are apparently all parts of one collection and have been so cited.

B. alpinum is very closely related to B. lindenii, and can be differentiated from that species only by the 4- rather than 5-merous flowers; all except 1 of the 73 examinable flowers among the,various collections ascribed here to B. alpinum were 4-merous. A part of the collections (Rimbach 21 p.p., Rimbach 137 p.p., Penland & Summers 325, Acosta 7231, Scolnik 1542) have leaves above and below glabrous except along the primaries on the lower surfaces, thus duplicating the more glabrous specimens of B. lindenii. The future disposition of B. alpinum will probably be as a subspecies of B. lindenii. B. alpinum may be differentiated from B. grisebacbii by a combination of rather insignificant characters which, however, give the Ecuadorian species quite a different aspect; drooping (rather than erect) more slender terminal peduncular internodes, predominantly 5-flowered inflorescences, pedicels longer below than above the pedicellar bracteoles, and much less acute petals. The smaller leaves, denser hypanthial pubescence, less-developed inflorescences, and quite different sepals separate B. alpinum from the small-leaved and glabrous element of B. sanguinolentum.