Scyphostelma bolivianum Y. M. Pineda, Liede & Meve, 2023

Pineda, Yam M., Keller, Héctor A., Balderrama-Torrico, José A., Meve, Ulrich, Nürk, Nicolai M. & Liede-Schumann, Sigrid, 2023, Phylogenetics in Scyphostelma (Apocynaceae: Orthosiinae) and description of new species, Willdenowia 53, pp. 83-112 : 87-89

1. Scyphostelma bolivianum Y. M. Pineda, Liede & Meve , sp. nov. – Fig. 1 , 3 , 4 .

Holotype: Bolivia, Cochabamba, Carrasco, 18–20 km from Montepuncu below Sehuenca, 19 Oct 1996, J. R. I. Wood 11598 ( K!; isotype: UBT!).

Diagnosis — Similar to Scyphostelma erikseniae (Morillo) Liede, Meve & Y. M. Pineda but with leaves ovatelanceolate (vs narrowly lanceolate in S. erikseniae), corona c. 4 mm in diam. with free staminal corona lobes c. 1.5 mm long (vs corona c. 5 mm in diam. and completely fused to a collar-like structure in S. erikseniae) and guide rails c. 1 mm long (vs c. 1.75 mm long in S. erikseniae).

Morphological description — Twining plants, to 4 m tall; stems densely pubescent with scattered trichomes; internodes of long shoots 40–53 × 1.2–2 mm, internodes of short shoots 25–31 × 1–1.5 mm. Leaves: petiole 9–17 mm long, with pubescence like that of stems; lamina ovate-lanceolate, 24–40 × 18–27 mm, base rounded, truncate to subcordate, apex acute to attenuate, usually mucronate; abaxial surface with short trichomes on veins, adaxial surface with sparse trichomes appressed, often with 2 conic colleters at base; venation brochidodromous with 3–7 pairs of secondary veins. Inflorescences axillary, alternate, with 5–8 flowers per cyme, all in simultaneous anthesis; peduncle 4.5–7 × c. 0.6 mm, with pubescence similar to shoots; bracts 0.7– 1 × 0.2–0.4 mm. Flowers: pedicel 11–12.5 × 0.2–0.35 mm, with scattered, wrinkled trichomes; calyx purple, lobes oblong, c. 1.5 × 1 mm, glabrous except for ciliate margin, apex acute; corolla maroon, rotate, c. 8 mm in diam., tube short, c. 0.1 mm long, free lobes elliptic, 3–3.2 × 1.8–2 mm, spreading, abaxially and adaxially glabrous. Gynostegial corona cream in vivo to yellowish in sicco, c. 4 mm in diam., spreading flat on corolla, basally fused, free staminal corona lobes rounded rectangular, 1.4– 1.8 × 1.1–1.3 mm; gynostegium stipitate, 1.5–2.1 × 2–3.2 mm, stipe 0.8–0.1 mm long; anthers rectangular, c. 1.2 × 1 mm, fertile part of anthers c. 1/2 as long as guide rails, abaxially bulging hemispherically, anther appendages suborbicular, c.

0.5 × 0.7 mm, translucent, guide rails forming a protruding triangle, 0.8–1 mm long; style head umbonate, c. 1.5 mm in diam. Pollinarium: corpusculum ovoid, 0.3–0.38 × 0.18–0.2 mm; caudicles strap-like with bend in central region, c. 0.15 mm long; pollinia ovoid-oblate, 0.3–0.34 × 0.2–0.22 mm, subapically attached to caudicles. Follicles and seeds not seen.

Phenology — Found with flowers in October.

Distribution and ecology — Scyphostelma bolivianum is presently known from two localities in Bolivia, one in La Paz and the other one in Cochabamba (Fig. 3, 4). The species inhabits well-developed moist cloud forests with areas of disturbance; scattered plants at the forest edge on a steep, scrubby bank by a river cliff; at altitudes between 2000–2500 m.

Etymology — The specific epithet refers to Bolivia, the country in which the new species has been recorded so far.

Additional specimens (paratypes) — BOLIVIA: La Paz, Sud Yungas, Huancané , 7.5 km hacia el sud sobre el camino nuevo, 2410 m, 10–20° SW, 9 Mar 1980 (sterile), S. G. Beck 3191 ( LPB!, MO, UBT!) .

Figures

Fig. 1. Phylogenetic reconstruction of Orthosiinae based on six cpDNA markers (see text), highlighting the position of the Scyphostelma harlingii clade. The remaining genera of Orthosiinae, Jobinia, Monsanima and Orthosia, with a sampling identical to Liede- Schumann & Meve (2013), are summarized by triangles, and so is the remainder of Scyphostelma. Numbers on branches indicate Bootstrap percentages / posterior probabilities. The root of the tree is that of Liede-Schumann & Meve (2013).

Fig. 3. Distribution map of Scyphostelma bolivianum (diamonds), S. erikseniae (circles), S. gra- cile (stars), S. harlingii (upright triangles), S. rotorum (square) and S. solomonii (inverted trian- gle). – Map created in QGIS (QGIS Development Team 2009).

Fig. 4. Scyphostelma bolivianum – A: flowering branch; B: flower; C: two anthers and guide rail; D: pollinarium; E: style head. – A–E from the holotype, J. R. I. Wood 11598 (K). – Drawn by Y. M. Pineda.