Carapichea urniformis (Steyerm.) C.M.Taylor (Taylor and Gereau 2013: 122)

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

9. Carapichea urniformis (Steyerm.) C.M.Taylor (Taylor and Gereau 2013: 122)

Psychotria urniformis Steyerm. ( Steyermark 1972: 556, figure 74)

Type.

GUYANA • Upper Mazaruni River Basin , Mount Ayanganna, along NE side; 800-900 m; 2 Aug. 1960; fr.; S.S. Tillett et al. 45008; holotype: NY [NY00132855]; isotypes: F [No. 1704839], COL [COL000004672], K [K000432825], NY [00146649] , US [00146649], VEN [No. 82281].

Description.

Shrub or small tree, up to 4 m tall, much branched; terminal branchlets terete or slightly quadrangular, 3-7 mm in diam., somewhat succulent, glabrous, soon covered with a buff corky bark. Stipules free, oblong-ovate, 7-12 × 7-9 mm, obtuse and entire when young (apical and distal nodes), later splitting into two lobes at older nodes, each lobe oblong-ovate, 4-9 mm long, shortly apiculate, soon corky, persistent or fragmenting. Leaves with petioles 1.0-3.5 cm long, glabrous; blades elliptic to oblong-elliptic, 12-22 × 5.5-10 cm, acute at base, acute at base, acuminate at apex, acumen narrowly triangular, 0.7-1.2 cm long, papyraceous to subcoriaceous, drying dark brown above and pale brown below, glabrous throughout; secondary veins 10-13 on each side of midrib, curving towards the margin and almost reaching it; tertiary veins rather densely and prominently reticulate in the dry state; domatia absent. Inflorescence capitate, short-pedunculate; peduncle 0.5-1.7 cm long, glabrous; head included in a large involucral structure, 5.5-9.0 cm long, green at base and pinkish-red at apex, formed by the basally fused bracts, glabrous; involucral basal portion urceolate, 2.5-5.7 × 2.3-3.5 cm, thick and fleshy, distal portion flaring, funnel-shaped, 2- to 4-lobed, lobes ovate to broadly ovate, 2.5-3.5 × 3.5-4.0 cm, membranaceous; internal bracts (when present) ligulate, orbicular to round, 1.7-2.5 × 1.0-1.7 cm; bracteoles ligulate to linear, 0.7-1.5 mm, glabrous. Flowers 5-merous, (heterostylous?), pedicellate; pedicels 1.0-3.5 mm long (5-7 mm long in mature fruits), glabrous. Hypanthium narrowly cylindrical, ca 1 mm long, glabrous. Disk bilobed to the base, ca 1 mm long. Calyx cupular, dentate, 1.0-1.7 mm long, glabrous; tube 0.7-1.0 mm long; teeth deltoid to narrowly triangular, 0.3-0.7 mm long. Corolla narrowly tubular, 18-31.5 mm long, glabrous, white; tube narrowly cylindrical, 17-30 mm long, 1.5-2.5 mm wide, glabrous outside, with a sericeous ring just above the base and glabrous above inside; lobes narrowly ovate, 1.0-1.5 × 0.7 mm, acute at apex, glabrous outside. Stamens inserted near the base of the corolla tube, included; anthers subsessile, linear, 3-4 × 0.2 mm, glabrous. Style barely exserted among the corolla lobes, 17-34 mm long, glabrous, branches oblong, 0.7-0.8 mm long. Fruits ovoid, 6-12 × 4.5-8.0 mm when dry ("20 × 15 mm" when fresh, fide Henkel & Hoffman 187), costate when dry, bright blue to bluish-purple. Pyrenes plano-convex, elliptic to ovate in outline, 5-10 × 3.0-6.5 mm, dorsal side 5-costate, ventral side longitudinally sulcate. Seeds with a deep ventral furrow, ± T-shaped in cross-section.

Distribution.

Endemic to Mount Ayanganna in western Guyana.

Ecology.

In understory of tall wet evergreen forest, on brown sandy lateritic soil, at 712-1100 m elevation.

Phenology.

One flowering specimen was collected in June, one specimen with flowers and young fruits was collected in November, and two specimens with mature fruits were collected in March and August.

Specimens examined.

GUYANA • Potaro-Siparuni Region, Mount Ayanganna , E face; 5°20 ’04” N, 59°55 ’30” W; 712 m; 4 Jun. 2001; fl., fr.; Clarke et al. 8963; MO n.v., NY , US • Cuyuni-Mazaruni Region, Pakaraima Mountains, toe slope on NW side of Mt. Ayanganna ; 5°24'N, 59°57'W; 1000-1100 m; 8 Nov. 1992; fl.; Henkel & Hoffman 187; K, MO n.v., NY, U , US • Mount Ayanganna , E slope, vicinity of new airstrip; 5°18 ’08” N, 59°50 ’10” W; 689 m; 9 Mar. 2014; fr.; Radosavlijevic et al. 103; MO n.v ., US.

Notes. This species is remarkable by its large, urn-shaped involucre, varying from bilobed to unequally 4-lobed, which is formed by the fusion of the external bracts. The involucre is reported to be red ( Taylor and Gereau 2013) although on the type label it is more precisely described as "green at base, shading through brown to pinkish-red at tips". Carapichea urniformis was placed by Taylor and Gereau (2013) in their Altsonii group, together with C. altsonii , C. nivea , and C. sandwithiana . However, as discussed above, it is quite different from these three species (which are here transferred to the genus Notopleura ) in characters of the stipules, leaf venation, and pyrenes, and is better placed in Taylor and Gereau’s (2013) Carapichea group, alongside with C. guianensis and C. galbaoensis , which are quite similar in vegetative characters. Due to the small number of collections, it is not known whether the flowers of this species are heterostylous. In the few flowers that we analyzed, the stamens are included and the style is barely exserted, which is consistent with a long-styled form.