Stelis stephanii B.Steud., 2011

Steudel, Bastian, 2011, A new species of Stelis (Pleurothallidinae, Orchidaceae) from South Yungas, Bolivia, Phytotaxa 38, pp. 49-52 : 49-51

Stelis stephanii B.Steud. , sp. nov. ( Fig. 1 & Fig. 2 )

Inter species Stelis sectionis Stelidis , habitu parvo caespitoso, foliis longi-petiolatis, racemo multifloro cum puncis negris, sepalis ellipticis cum punctis negris, et labello triangulari.

Holotype: — BOLIVIA. South Yungas : Chulumani, 16° 18,539`S, 67° 32,888`W, 2180 m, S.Beck 30762 (LPB!).

Plant large, epiphytic, caespitose, roots slender. Ramicauls erect, stout, 5–8 cm, enclosed by a loose, tubular sheath, and another at the base. Leaf erect, elliptical, 6–11 cm, 1.6–2.5 cm wide. Inflorescence an erect, flexous and curved raceme, several flowered in the upper half, 15–20 cm long and black dotted. Sepals yellowish to greenish with black dots at the dorsal side, some of them translucent to the ventral side, haired at the outer margins of the ventral side, 3-veined, 2.5–3.0 mm long, 1.8–2.2 mm wide. Petals yellowish to greenish, 1-veined, 1 mm wide. Lip thick, triangulate, papillous, 1 mm long, 0.8 mm wide. Colomn stout, 0.8 mm long, 0.7 mm wide, stigma bilobed.

Distribution:—Known only from the type locality at Chulumani, Bolivia, elevation about 2150–2200 m in highly disturbed, montane forest. Several individuals were observed in the canopy of different tree species.

Etymology:—The epithet honours Dr. Stephan Beck who collected the specimen of this new species and assisted me many times with logistical and administative support in Bolivia.

Discussion:— Stelis stephanii belongs to section Stelis , which is characterised by the widely spreading and equally sized sepals ( Luer 2009). It may be related to the species complex of Stelis argentata Lindley (1842: 64) , which is documented from Bolivia as well. Stelis stephanii differs from species of this complex in the triangulate lip and the partially pubescent sepals. The lip of Stelis stephanii is unusually long and papillous, in the complex of Stelis argentata the lip is transversely subquadrate ( Luer 2009). In the complex of Stelis argentata the hairs are on the whole sepal or absent and shorter than those of Stelis stephanii which are there only on the margins of the sepals. With its total height of about 14–20 cm, the new species is relatively large for the genus Stelis , but in some species of Stelis size can vary markedly.

Figures

FIGURE 1. Habit of the whole plant (Beck 30762).

FIGURE 2. A. Flower on a horizontal part of the inflorescense. B. Sepals, hairs are only drawn in the left part to show the black spots. C. Petal. D. Lip in top view. E. Lip in side view. F. Column.