Scyphostelma unguiculatum (Britton) Liede, Meve & Y. M. Pineda, 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 : 101-103

Scyphostelma unguiculatum (Britton) Liede, Meve & Y. M. Pineda , comb. nov.

≡ Vincetoxicum unguiculatum Britton in Bull. Torrey Bot. Club 25: 499. 1898 ≡ Cynanchum unguiculatum (Britton) Markgr. in Notizbl. Bot. Gart. Berlin-Dahlem 11: 788. 1933.

– Lectotype (designated here): Bolivia, La Paz, Unduavi, 8000 ft, Oct 1885, H. H. Rusby 1044 (NY01288243!) . – Fig. 14 , Appendix S2, S3.

Nomenclatural note — Of the syntypes cited in the protologue, Rusby 2518 (NY01288245!, NY01288246!) and Rusby 1044 (NY01288243!, NY01288244!), one specimen bears a pollinarium drawing, and the printed description by Britton, and is therefore selected here as the lectotype of Vincetoxicum unguiculatum . Markgraf’s (in Pilger 1933: 788) citing “ Peru: Ruiz et Pavon” on publishing Cynanchum unguiculatum can be considered an indirect reference to Britton’s (in Rusby 1898: 499) “ Vincetoxicum unguiculatum (R. & P.) Britton” (cf. Turland & al. 2018: Art. 41 Ex. 3 and 7). The Peruvian specimens of Ruiz and Pavón to which Markgraf (1933) was referring, H. Ruiz & J. A. Pavón 5/80 (F V0040239F digital image!, MA814543!, MA814544!, MO-2290015!), conform to the concept of S. unguiculatum .

Remarks — Scyphostelma unguiculatum is one of the most frequent species of Scyphostelma around La Paz. It is multi-leaved with fairly stout stems covered by an obvious hispid to tomentose indumentum; the flowers are medium-sized (c. 5 mm in diam.), the corolla whitish and tomentose and the bowl-shaped corona whitish to rose-coloured; the follicles are puberulent to pubescent ( Fig. 14 ).

Figures

Fig. 14. Scyphostelma unguiculatum – A: branch with inflorescences and twin follicles; B: flower, two corolla lobes removed; C: gynostegium and corona; D 1: pollinarium, one pollinium removed; D 2: pollinarium; E: style head. – A, B, E from S. Liede & J. Conrad 3140 (UBT); C, D1 from H. Ruiz & J. A. Pavón 5/80 (MA814543); D2 from J. R. I.Wood 10086 (LPB). – A, B, E drawn by J. Conrad; C, D drawn by U. Meve.