Prescottia ecuadorensis C.O.Azevedo & Van den Berg

De Azevedo, Cecília O. & Berg, Cássio Van Den, 2012, Prescottia ecuadorensis: a new species of Prescottia (Cranichidinae, Orchidaceae) from Ecuador, Phytotaxa 40, pp. 60-64 : 60-63

Prescottia ecuadorensis C.O.Azevedo & Van den Berg , sp. nov.

Prescottia lojana et P. stachyodes foliis longe petiolatis et floribus viridibus cum labello intus glabro similis et illa labello cum vena centrali prominenti praesertim similis. Ab P. stachyodes labello sine vena prominenti et ab ambabus folio deltoide (in P. lojana folio ovato et P. stachyodes folio elliptico-ovato), praeterea ab utroque speciebus scilicet seminis intercelularibus spatiis destituta differt.

Type:— ECUADOR. Loja: Parque Nacional Podocarpus, Vicinity of Lagunas de Compadre , ca. 6 hours walking from centro de información, 21 November 1989, Madsen & Pedersen 86457 (holotype MO 4645295!). Fig. 1 .

Terrestrial herb. Leaves non-articulate, at least 2, basal, petiolate; petiole 3.2–3.5 cm long; blade 3.7–4.0 × 2.7–3.3 cm, fleshy to coriaceous, deltoid, apex acute, base truncate. Inflorescence terminal, erect, dense, at least 55-flowered; peduncle at least 19.0 × 0.4–0.5 cm; peduncle bracts at least 6, 20–40 × 8–10 mm, ovate, apex acute; raceme at least 8.0 × 1.2 cm. Flower bracts 5.9–6.1 × 2.2–2.5 mm, ovate, apex acute. Flower sessile, erect, non-resupinate; dorsal sepal strongly revolute 2.9–3.2 × 1.0 mm, lanceolate to oblong, apex obtuse, lateral sepals basally connate, forming a sepaline cup, adpressed to the lip, strongly revolute, 3.7–4.0 × 1.0– 1.2 mm, lanceolate to ovate, apex obtuse; petals strongly revolute, 2.9–3.0 × 0.8 mm, linear, apex obtuse; lip 3.0–3.5 × 1.8–2.3 mm, fleshy, midvein prominent, deeply concave, cucullate, enclosing column, inner surface glabrous, provided at the base with two fleshy, parallel, fusiform-cylindrical nectaries, which are 0.5–1.0 mm long; column erect, 2.0 × 1.2 mm, glabrous; provided with two lateral wing-like staminodes; stigmatic surface convex; anther erect. Fruits erect, ellipsoidal.

Distribution:—Vicinity of Loja, Ecuador.

Habitat:—Ridge-top vegetation of elfin forest and páramos, at elevations of 3,000–3,400 m.

Conservation status:—Data Deficient (DD). It is known only from one location, represented by a single specimen.

Etymology:—In reference to the country where the type specimen was collected.

Notes:—There are two duplicates of the collection Madsen & Pedersen 86457, the first deposited at MO and the other at AAU, which represent different species. The material at AAU is a specimen of Prescottia lojana . It was cited in the protologue of P. lojana ’s ( Dodson 1996) among the “other specimens seen,” which included seven collections. Although the specimen at MO initially appeared to be determined by Dodson, we believe that he did not see it, first, because he did not cite it in the original description of P. lojana , and, second, it was not annotated in Dodson´s handwriting like the material at AAU. Most probably, the MO specimen was identified by somebody else as P. lojana only because it was a duplicate of the AAU material. The specimen deposited at MO belongs to a different species, which is described here.

Morphologically, Prescottia ecuadorensis appears to belong to the long petiolate-leaved species group that includes P. carnosa Schweinfurth (1951: 173) , P. lojana and P. stachyodes . Prescottia carnosa occurs only in Venezuela and Guyana and the other two in Ecuador. Prescottia carnosa can be easily distinguished from the others by the position of its flowers, which are almost patent, and also by its lip with a longitudinal keel or septum. The other species have erect flowers and lip without a keel or septum. Prescottia ecuadorensis can be distinguished from these taxa by its leaves, inflorescence, flowers and seeds. Prescottia ecuadorensis has multiflorous, congested inflorescences, whereas in the others these are more lax. It has deltoid leaves, whereas P. lojana and P. stachyodes have elliptic to ovate leaves. The leaves and lips of Prescottia ecuadorensis and P. lojana are smaller than those of P. stachyodes ; in P. ecuadorensis leaf blades are 3.7–4.0 × 2.7–3.3 cm and lip 3.0–3.5 × 1.8–2.3 mm, whereas in P. lojana leaf blades are (4.5–)7.5–10.0 × (2.5–) 4.3–5.2 cm and lip (3.7–)5.0–6.6 × 1.8–2.2 mm.

Prescottia ecuadorensis can be also distinguished from these species by its seeds. Prescottia carnosa has oblong seeds with triangular intercellular spaces at the angles of the testa cells [ Fig. 1–2 ], whereas in P. lojana intercellular spaces are circular and located all around the testa cells [Fig. 3–4]. In P. ecuadorensis the seeds are fusiform, without intercellular spaces [Fig. 5–6], whereas P. stachyodes has linear seeds with the anticlinal testa cell walls more or less split with a series of small fusiform intercellular spaces with beaded appearance [Fig. 7–8].

Figures

FIGURE 1. Holotype of Prescottia ecuadorensis (Madsen & Pedersen 86457, MO).

FIGURE 2. 1–8 Scanning electron micrographs of Prescottia seeds. 1–2 Prescottia carnosa (Steyermark 59772). 3–4 Prescottia lojana (Holst 3522). 5–6 Prescottia s ecuadorensis (Madsen & Pedersen 86457). 7–8 Prescottia stachyodes (Harris 10096).