Sphyrospermum revolutum Luteyn, 2013

Luteyn, James L. & Pedraza-Peñalosa, Paola, 2013, Nomenclature, taxonomy, and conservation of the neotropical genus Sphyrospermum (Ericaceae: Vaccinieae), including five new species for Colombia, Ecuador, and Peru, Phytotaxa 79 (1), pp. 1-29 : 20-22

Sphyrospermum revolutum Luteyn , sp. nov. ( Fig. 4 )

A Sphyrospermo linearifolio habitu lianoideo, foliis bullatis, pedicellis calycibusque pilosis (non glabris), calyce majore, 3.3–4 (non ca. 2–2.2) mm longo, lobis longioribus, ca. 1.5 (non 0.2–0.6) mm longis, corolla virescenti-cremea (non roseo vel subroseolo) cylindracea (non urceolata), longiore, 8.5–9 (non 5–6) mm longa staminibus 10 (non 5), distributione geographica differt.

Type: — ECUADOR. Morona-Santiago: Limón– La Unión road, trail beyond end of road (= 13.6 km from Limón) towards La Unión , ca. 2°59’S, 78°25’W, 1340–1370 m, 18 November 1998 (fl), Luteyn & Mogollón 15378 (holotype NY!; isotypes AAU!, COL!, MO!, QCA!, QCNE!, TEX!) .

Scrambling, lianoid shrubs; stems subterete, broadly and bluntly angled, ca. 3.5–4 mm diam., glabrous; twigs subterete to flattened, angled, striate, puberulent with white trichomes. Leaves thin-coriaceous, slightly bullate, narrowly lanceolate, ca. 5.5–9 × 0.9–1.3 cm, base narrowly rounded to obtuse, apex long-acuminate, the tip itself blunt, margin narrowly to strongly revolute over entire length, lamina glabrous above, with few, scattered, reddish to blackish glandular hairs ca. 0.1 mm long beneath; obscurely 3(–5)-plinerved, midrib sometimes thickened and raised in proximal ca. 2 mm but usually thin and totally impressed distally above, raised and prominent beneath, lateral nerves (when visible) impressed above and raised beneath, tertiary veinlets obscure; petiole terete, rugose, ca. 1.5–2.5 mm long, puberulent to glabrate. Inflorescences axillary, flowers solitary, loosely pendent, much shorter than the subtending leaves; floral bract 1, ovate, rounded, ca. 0.4 mm long, ciliate with glandular hairs; pedicel terete, ca. 10–14 × 0.2–0.3 mm, puberulent; bracteoles 2, basal, opposite to slightly subopposite, linear-lanceolate, acuminate, ca. 0.3 mm long, ciliate with glandular hairs. Flowers 5-merous, diplostemonous; calyx ca. 3.3–4 mm long, densely to weakly short-pilose with eglandular hairs, also with few, reddish, glandular hairs; tube cylindric-obconic, sometimes weakly pentagonal, ca. 1.6–2 mm long; limb wide-spreading, ca. 1.8–2 mm long; lobes triangular to ovate-triangular, short-acuminate, ca. 1.5 mm long, the short-pilose hairs eglandular; sinuses broadly rounded; corolla bistratose, cylindric but slightly broadening distally to throat, ca. 8.5–9 mm long and 3–4.5 mm diam., pale greenish-cream, sometimes with a rose hue, with few glandular hairs without, the lobes reflexed but not exposing stamen tips at anthesis, deltate, acute, ca. 1.5 mm long; stamens 10, equal in length, ca. 8 mm long; filaments ca. 3.5 mm long, pilose distally; anthers ca. 5 mm long; thecae ca. 1.7 mm long, the base straight, without basal appendage, smooth; tubules ca. 3.3 mm long, dehiscing by clefts ca. 1.2 mm long; style to 9.5 mm long, exserted. Berry unknown.

Distribution and phenology:— Sphyrospermum revolutum is endemic to eastern Ecuador (Prov. Morona- Santiago), the “Oriente” region, and known only from the type collection which was flowering in November. It was collected in primary forest over sandstone substrate, at 1340–1370 m.

Conservation status:— The type collection was made from the edge of a remnant forest in an area not so frequently collected by botanists, but deteriorated and with high logging activity. Critically endangered [ CR B1 ab(i, iii, iv)] .

Observations:— Sphyrospermum revolutum is characterized by having revolute, slightly bullate and narrowly lanceolate leaves, flowers 5-merous with short-pilose pedicels and calyces, corollas that are glabrous and greenish-cream colored, and 10 stamens. Sphyrospermum revolutum is similar to S. linearifolium (NY isotype sterile) from Costa Rica ( Morales & Rodríguez 2005); the latter species differs by its more glabrous and non-lianoid habit, non-bullate leaves that are acute apically, much longer pedicels, smaller flowers with white corollas, and fewer stamens. Both species are known only from their type specimens, so more collections are needed to evaluate the range of the characters and interspecific relationships.

Figures

FIGURE 4. Sphyrospermum revolutum. A. Branches. B. Leaf showing undersurface and detail of cross-section showing revolute margin. C. Floral bud. D. Mature flower showing pedicel, calyx, and corolla. E. Longitudinal section of calyx showing ovules. F. Stamens showing lateral, dorsal, and two ventral views. G. Twig with a post anthesis calyx. Illustration by Bobbi Angell (drawn from holotype).