Carapichea, Lachenaud & Delprete, 2022

Lachenaud, Olivier & Delprete, Piero, 2022, Revision of Carapichea (Rubiaceae - Psychotrieae) in the Guianas, with two new combinations and transfer of three species to Notopleura, Plant Ecology and Evolution 155 (2), pp. 275-300 : 275

6. Carapichea sp. A.

Description.

Shrub, up to 1 m tall, glabrous; terminal internodes terete, 3-4 mm in diam. Stipular sheath truncate to shallowly ovate, 2-4.5 mm long, glabrous, persistent. Leaves with petioles 1.6-2.7 cm long, glabrous; blades narrowly oblong-elliptic, oblong-lanceolate to oblong-oblanceolate, 15-25 × 3.5-6.5 cm, acute-decurrent at base, acute and acuminate at apex, acumen narrowly triangular, 1.2-1.3 cm long, drying papyraceous and brown, glabrous throughout; secondary veins 17-22 on each side of midrib, with 2-3 intersecondary veins between each pair of secondary veins; tertiary venation reticulate; domatia absent. Inflorescence terminal, long-pedunculate, distally short-trichotomous, peduncle 8.2-8.5 cm long, glabrous, drying brown; branches 4-6 mm long, thick-fleshy, puberulous, terminating into cymules; each cymule subtended by 1-2 bracts; bracts unequal within each cymule, narrowly lanceolate to narrowly oblong-lanceolate, the longer ones 14 × 5.2 mm, the shorter ones 4.0 × 2.6 mm, persistent, drying brown. Hypanthium narrowly obovoid, 2.5 mm long. Calyx cupular, 0.7 mm long, undulate, glabrous. Corolla unknown (fallen off). Style 4 mm long, lobes narrowly elliptic (after corolla has fallen off). Fruits unknown.

Distribution.

Only known by two gatherings from the Kamoa Mountains, Guyana.

Ecology.

Understory of dense forest on brown sand with rocky outcrops, at 240-400 m elevation.

Phenology.

The two flowering collections were collected in November.

Specimens examined.

GUYANA • Upper Takutu-Upper Essequibo Region, Kamoa Mountains, 0-2 km N of camp on Kamoa River ; 1°31'N, 58°49'W; 240 m; 11 Nov. 1996; fl.; Clarke 3081; MO , US • Upper Takutu-Upper Essequibo Region, Kamoa Mountains , 1.5 km S of Kamoa River; 1°31'N, 58°49'W; 400 m; 12 Nov. 1996; fl.; Clarke 3136; MO , US.

Notes.

This probably new taxon is only known from two gatherings, both of which have inflorescences but no corollas left (one specimen still has a fully elongated style) and no fruits. It closely resembles C. araguariensis and C. necopinata , both of which are so far only known from Brazil. The differences with the former species are indicated in the key. From the latter species, which is still only known from the type ( Taylor and Gereau 2013: 120), it may be separated by its smaller bracts (the largest ones up to 14 mm long vs 20-25 mm long in C. necopinata ), longer inflorescence peduncle (8.2-8.5 cm long vs 5.0-5.5 cm long), shorter calyx (0.7 mm long vs 1.5-2.0 mm long) and leaves with 17-22 (vs 22-24) secondary veins on each side of the midrib. With so little material, it is difficult to assess the significance of these characters, and better collections are required to establish the identity of this taxon.