Peter C. Hoch and Peter H. Raven

Epilobium leiospermum Hausskn., Monogr. Epil. 206, t. 5 fig. 45. 1884; H. LJv., Ic. Gen. Epil. t. 65. 1910; Raven, Bull. Brit. Mus. (Nat. Hist.) Bot. 2: 357. 1962; in Rech. f., Fl. Iran. 7: 11. 1964; Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 506. 1972. Lectotype: Baltistan: near Tarshing, north-west of Astor, 10-24 Sept. 1856, Schlagintweit s.n. (JE). Epilobium tetragonum sensu Aitch., J. Linn. Soc., Bot. 18: 60. 1880, pro parte, non L. Epilobium cylindricum sensu Wendelbo, Nytt Mag. Bot. l: 46. 1952, non D. Don. Epilobium nuristanicum Rech. f., Biol. Skr. Dansk. Vid. Selsk. x, 3: 61. 1958. Type: Afghanistan, Nuristan, wet meadow above Paschki in Parun Valley, 2 Aug. 1935, Kerstan 1382 (W).

Slender erect perennial herbs, sprouting from base or forming loose leafy basal rosette; stem 15-60 cm tall, simple or loosely branched above, glabrescent, with raised lines decurrent from the margins of the petioles, the lines sometimes sparsely strigillose. Leaves 2.6-7.1 x 0.6-1.7 cm, oblong-lanceolate to narrow lanceolate, subglabrous except for sparse strigillose margins and veins, the margins usually coarsely denticulate, subcoriaceous, acute, narrowly obtuse base to petiole 3-6 mm long. Inflorescence erect, crowded, dense strigillose and eglandular. Sepals 2.8-5.5 x 0.9-2.1 mm, strigillose. Petals 4-9 mm long, pale rose or pink, rarely white. Style 2.8-4 mm long. Stigma subcapitate to short clavate, surrounded by anthers at anthesis. Capsules 5-8.5 cm long, on pedicels 1-3.2 cm long. Seeds 0.9-1.3 x 0.34-0.46 mm, narrow obovoid, foveolate (smooth), the chalazal collar nearly absent; comas 4-5.5 mm long, dingy, easily deciduous.

Type: Baltistan, Thalle La to Bagmaharal, 30 Aug. 1856, Schlagintweit 5909 (JE!, holotype).

Distribution: Western Himalaya from northeastern Afghanistan and the Murree Hills to western Nepal, the Chumpi Valley and the vicinity of Lhasa, Tibet.

Raven (1962) commented that the relationship between E. leiospermum and E. tibetanum was very close, and warranted careful examination. Following the treatment of Haussknecht (1884), he distinguished them on the basis of different stigma shapes and size differences in leaves and flowers. Analysis of recent collections shows great variability in these characters, without a clear line of distinction, even in terms of stigma shape. Plants with large flowers tend to have more capitate stigmas, and probably out-cross more frequently than smaller-flowered plants. In the absence of careful fieldwork, it seems best not to recognize these differences at the specific level, in keeping with recent treatments of other variable species of Epilobium that include both selfmg and outcrossing populations. Fl. Per.: Jun-Sep. Fr. Per.: Jul-Oct.