Amaioua macrosepala C. H. Persson & E. Méndez, 2015

Persson, Claes & Vargas, Enrique Méndez, 2015, A striking new species of Amaioua (Gardenieae-Rubiaceae) from the Colombian Andes, Phytotaxa 213 (1), pp. 65-68 : 65-67

Amaioua macrosepala C. H. Persson & E. Méndez sp. nov., Fig. 1 A–D

Type:— COLOMBIA. Caldas: Mun. Pensilvania, vereda El Congal, microcuenca El Congal, 05°22’51.3’’N, 75°07’00.1’’W, 2079 m, 6–12 August 2013 (fr), E. Méndez Vargas 7015 (holotype CUVC 052852 !; isotype GB-0147061!) .

Supposedly dioecious shrub, 2–5 m tall. Branchlets 4–7 mm thick, densely sericeous. Stipules forming a circumscissile cap over the shoot apex, shed immediately as shoot extends, elliptic to slightly ovate, to 20 mm long, densely sericeous outside, glabrous inside with 1–1.5 mm long reddish colleters at base, apex acute. Leaves opposite, subsessile; petioles 2–4 × ca. 1.5 mm, sericeous; blades slightly elliptic-obovate, 13–22 × 4–6.5 cm, papyraceous, acute at base, acuminate at apex with acumen to 2.8 cm long, glabrous or sparsely hirtellous above, densely sericeous along the prominent midvein and the prominulous secondary veins below, tertiary and quaternary venation distinct, secondary veins 15–20 on each side of the midrib; domatia absent. Flowers unknown. Young fruit pubescent. Infructescence a cyme or umbellike cyme with 3–5 fruits; fruits rarely solitary, terminal, sessile or with peduncle to 6 mm long, pedicels 1.5–2.5 cm long, sericeous. Fruits globose, 1.5–2.0 × 1.5–2.0 cm, puberulent, green when fresh, brown when dry, crowned by a persistent calyx with foliaceous lobes, calyx tube very short, to 1 mm long; lobes 5, contorted, imbricate or sometimes open, elliptic, 1.4–1.7 × 0.8–1.2 cm, conspicuously narrower at base, acute to shortly acuminate at apex, midvein wide and distinct, secondary veins distinct and numerous, lobes minutely puberulent above, densely puberulent or sericeous along veins beneath. Seeds numerous, embedded in a placental pulp; immature seeds lenticular, 7 x 5 x 0.5 mm.

Distribution and habitat: — Amaioua macrosepala is endemic to the Central cordillera of the Colombian Andes where it occurs in the understory of cloud forests at 1700–2080 m elevation.

Conservation status: According to the IUCN Red list ( IUCN 2010) Amaioua macrosepala is considered Endangered (EN subcriteria B2a—severely fragmented or known to exist at no more than five locations) as it is known to occur only in two localities not subjected to conservation.

Phenology: —Fruiting collections were made in January, June and August.

Amaioua macrosepala is presumably a dioecious shrub similar to Amaioua pedicellata Dwyer (1980: 30) by sometimes having an umbelliform infructescence and globose fruits. It differs from all other Amaioua species in having large leaf-like, almost free, calyx lobes vs. small linear lobes of a few mm in length. Duroia valesca C.H. Persson & Delprete (2010: 525) and Riodocea pulcherrima Delprete (1999: 18) , from the Atlantic forest of SE Brazil, have similar leaf-like calyx lobes, but both of these species differ from Amaioua in having solitary fruits and calyx lobes clearly overlapping. In addition, Duroia valesca is immediately distinguished by its 4(5)-whorled leaves vs. opposite in A. macrosepala , and R. pulcherrima differs in having large foliose persistent stipules vs. calyptrate caducuous stipules in A. macrosepala .

Etymology: —The specific epithet of this species refers to the large leaf-like calyx lobes that are fused at the base (calyx tube to 1 mm long).

Additional specimens examined (Paratypes): — COLOMBIA. Antioquia: Mun. Santo Domingo, Cgto. Santiago, vertiente oriental de la Cordillera Central, 6°32’56.2”N, 75°08’41.1”W, 1704 m, 20 June 2014 (fr), A. Camargo García 855 (HUA photo). Caldas: Mun. Pensilvania, Vereda El Congal, finca El Congal, 05°22’51.3’’N, 75° 07’00.1’’W, 2079 m, 21 February 2014 (fr), E. Méndez Vargas & N. Londoño 7354 (CUVC, GB).

Figures

FIGURE 1.A–D. Amaioua macrosepala. A. Infructescence. B. Leaf-like sepals seen from above. C. Calyptrate stipule. D. Solitary young fruit. Photos from the type, E. Méndez Vargas 7015, by Enrique Méndez Vargas.