Silene thomsonii Majumdar, J. Indian Bot. Soc.

Lidén, Magnus & Oxelman, Bengt, 2023, FLORA OF NEPAL NOTULAE IV: NEW SPECIES AND RESURRECTED NAMES IN SILENE, Edinburgh Journal of Botany 80 (367), pp. 1-28 : 9-14

4. Silene thomsonii Majumdar, J. Indian Bot. Soc. 42: 650 (1963) [1964], nomen novum for

Lychnis nutans Benth. in Royle, Ill. Bot. Himal. Mts. 1(3): 80 (1839), nomen illegit., non L. nutans (L) Scop. (1771). – Melandrium nutans (Benth.) Walp., Rep. Bot. Syst. 1: 281 (1842) comb. illeg. – L. ciliata Wall. , nom. nud. – Type: Nepal, Gosain Than. 27 x 1821, Wallich cat. 621 (lectotype K000728832, here designated; selected because it hails from “Herbarium Benthamianum”; isolectotypes BM000521649, E00015049, G00074039, K000728833, K001111425). Figures 3 , 4 .

Silene fissicalyx Bocquet & Chater, Enum. Fl. Pl. Nepal 2: 55 (1979). – Type : C. Nepal, Rasuwa , W Mailung Khola drainage area S of Ganesh Himal., 10 ix 1975, A. Stainton 7466 (holotype BM000521520 , not seen; paratype Yon 276 E00783708 ).

Melandrium dingriense Y.W.Tsui & P.Ke ex L.H.Zhou, Fl. Xizang. 1: 716 (1983). – Type: Tingri , Da-ge-zhang, 4200 m, 29 vii 1959, Xizang exp. 676 (holotype PE 00935112 ).

“ Melandrium cashmerianum ” sensu Zhou (1983) p.p., non (Royle ex Benth.) Majumdar (1964).

“ Silene indica ” sensu Bocquet (1969) p.p. and Rajbhandari & Suzuki (2008) p.p., non Otth (1824).

“ Silene cancellata ” sensu Bocquet (1969) p.p., non (Jacquem. ex Edgew. & Hook.f.) Majumdar (1964).

Because Silene thomsonii has been so often confused with other taxa, in particular with the very dissimilar S. indica (see Lidén, 2019b), a portrait of this very distinct and common species is needed. Although arguably the most variable of all Silene species in Nepal (see below), it exhibits some striking characters (in bold print below) that make it unique among Central Himalayan Silene species.

Perennial caespitose herb, pubescent throughout with down-curved eglandular hairs and patent glandular hairs. Stems few to many, ascending to suberect, 10–40 cm long, simple, with 5–8 pairs of rather equally sized leaves. Leaves pubescent with short acute non-glandular hairs, ovate to broadly elliptic or obovate, often abruptly shortly acuminate; lower leaves cuneate into short petiole, middle and upper leaves sessile, (8–)15–40 ×

7–20 mm; uppermost leaves (bracts) often smaller. Inflorescence very lax, 1- to 5-flowered (to 10-flowered in lowland forms), often widely spreading. Flowers nodding, becoming erect in fruit. Calyx 8–13 mm, pale green to whitish-translucent, 5-angular, divided to at least 1/2; teeth very densely long-ciliate with white or purplish hairs; veins prominently raised, dark green to purple, densely dark-purple pubescent with straight glandular hairs and shorter non-glandular hairs; commissural veins bifurcating almost from base or shortly above, confluent with midveins apically; lateral anastomoses absent. Androgynophore 3 mm long, densely woolly-hairy. Petal claw auriculate, entire to obtusely dentate apically. Petal limb 1.5–2.5 mm long, shallowly bifid. Styles 5, exserted. Seeds 1 mm, tuberculate, with long dorsal papillae.

Distribution. Endemic to Central Nepal and adjacent South Tibet.

Habitat and ecology. Habitat preferences wide, judging from labels: “rocky slope; sandy slope; sandy grassland slope; rock ledges; grazed grassland”, and for low-altitude records, “open damp place; open grassland near field; eroded trail side”. Altitudinal range (1900–) 2300–4700 m. Flowering late July to early September; fruiting August to September.

Notes. Slightly protandrous. Plants with flowers that apparently lack stamens have been encountered, but this needs confirmation.

Silene thomsonii has an extreme altitudinal range (1900–4700 m) and varies greatly in general vegetative appearance and number, size and width of flowers. Three main variants can be distinguished:

a) This form, which includes the type specimen of Silene thomsonii , is the most widespread: Figures 3 B,C , 4 C . Silene fissicalyx was based on plants from Ganesh Himal in Central Nepal with short few-flowered stems and small leaves. However, because there are transitional stages in the same area to more floriferous and larger plants, we find that it does not deserve distinction.

b) Lowland forms occurring between 1900 and 3000 m ( Figures 3 A , 4 B ), often from field margins or roadsides, are usually paler green, long and slender, more branched and with more numerous smaller, paler and often narrower flowers (M. Suzuki et al. 9485253, N.P. Manandhar 9873, F. Miyamoto et al. 9430120, E. Byers 12, S.K. Kasaju 810). They are widely scattered throughout the distribution area of the species and are not necessarily related.

c) Plants from the Solukhumbu district ( Figures 3 D , 4 A ) in the easternmost part of the distribution area have a different habit with fewer nodes, longer-lasting flowers and longer basal leaves, and wide synflorescences; a case could certainly be made for subspecific distinction.

Silene cancellata (Jacquem. ex Edgew. & Hook.f.) Majumdar , a species endemic to the border area of Himachal Pradesh and Kashmir, has been erroneously reported from Nepal ( Bocquet, 1969) based on specimens of S. thomsonii but is easily distinguished by its short pedicels, calyx divided to 3/4 or more with lanceolate acute teeth, long exserted petals with much longer limb and low-colliculate flat-backed seeds.

The related Silene bhutanica (W.W.Sm.) Majumdar from East Himalaya and Southeast Tibet differs from S. thomsonii in its longer and narrower leaves and longer and less divided calyx. It has been erroneously reported from Nepal.

Additional specimens examined. NEPAL. Rukum: Above Guibang (28°42′N, 82°56′5′′E), 3225 m, 28 viii 2014, C. Pendry et al . BRD A137 ( E00898984 ). Mustang: Titigaon , 2610 m, 6 viii 1996, T. Hoshino et al. ( E00826275 , TI 9666181 ) . Manang: Chame , 2700 m, on open and rocky land, 15 viii 1983 ,

N.P. Manandhar 9873 (KATH; small-flowered); Marsyandi Khola, 7 viii 1983, H. Ohba et al. 8311145

(TI 8311145). Gorkha: near Lungdang Gompa, 2840 m, 28 vii 1994, M. Suzuki et al. ( PE 01698863 ,

TI 9470233 ); Ranagaon, 1900 m, 3 viii 1994, M. Suzuki et al. 9485253 ( E00223990 , PE 01522757 ,

TI 9485253 , extreme lowland form ). Rasuwa: Chyauche Kharka (28°14′N, 85°07′E), 2325 m, 12 viii

1994, F. Miyamoto et al. 9430120 ( E00152785 , TI) ; Ganesh Himal (28°20′N, 85°10′E), v 1974, B. Yon 256 ( E00826675 , filed as Silene fissicalyx ) ; Bhairavkunda , 4100 m, 14 vii 1972, A. Maire 59 ( E00783706 , filed as S. fissicalyx ) ; Buddha Mandir (28°05′05′′N, 85°24′11′′E), 4370 m, 16 ix 2016, M. F. Watson et al. A216 ( E) ; Gosainkund (28°05′N, 85°25′E), 4300 m, 12 viii 1974, J. H. de Haas 2234 ( L, filed as S. fissicalyx ; Z) ; Tiru Danda ridge (28°12′N, 85°13′E), 4000 m, 23 viii 1974, J. H. de Haas 2565 ( BM; L, filed as S. fissicalyx ; Z) ; Langtang , 3350 m, 21 viii 2000, M. N. Subedi 00400293 ( KATH) ; Langtang , Kyangjin (28°13′N, 85°34′E), alpine Weidin , Zwergstrauch-heiden, Schutthalden, 4000 m, 10 viii 1995, K. Reiter & WÜndisch s.n. ( M) ; Langtang , stony pasture, 27 viii 1976, Durham univ. Him. Exp. D35 ( KATH019178 ) ; Langtang , Ghora Tabela , 3000 m, 10 ix 2009, K. Halberg 268 (photograph). Sindhu-palchok: Charikot to Kalinchok, 8000 ft, s.d., Banerji , Shrestha & Upadhyay 2756 ( KATH) ; Michet , 13,000 –14,000 ft, 1927, Wigram 1927 ( E00219983 ) ; Kharidhunga , 2650 m, 6 ix 2017, S. K. Kasaju 810 (efloraofindia, small-flowered lowland form). Dolkha: 13 x 1960, S. B. Malla & S. B. Rajbhandari 436 ( KATH) ; Dongang to Beding, 17 ix 2007, S. Noshiro et al. 20720039 ( E00477130 , TI). Solukhumbu: Namche Bazar to Kyangjuma (27°48′39′′N, 86°43′25′′E), 3550 m, 14 ix 2005, DNEP3 AY36 ( E00248396 ) ; Chule (27°58′N, 86°38′E), E facing slope, 4718 m, 21 ix 2005, DNEP3 BX186 ( KATH) ; Mt Everest national park , drainage of Imje Khola, Pangboche S slope, 4030 m, 26 vii 1984, A. & E. Byers 432 ( COLO) ; Tangnag (c. 27°42′N, 86°50′E), 4060 m, 21 viii 1997, M. Wakabayashi et al. 9710312 ( E00241851 , TI) ; Namche to Jorsale, eroded trailside, 3280 m ,

4 ix 2017, E. Byers 12 (photograph of living plant, no specimen, collection number EAB 20170904-12) ; Syangboche, 3840 m, 7 viii 2017, E. Byers 165 (photograph of living plant, no specimen, collection number EAB 20170904-165) ; Loco ignoto: 12 viii [year not known], K.R. [Rajbandhari?] 0749 (KATH, unmounted in 2018); ibid., 4 viii, K. R. 0504 ( KATH, unmounted) ; ibid., 3 viii [year not known], K. R. 0449 ( KATH, unmounted) ; ibid., 20 viii [year not known], K. R. 9740430 ( KATH, unmounted) .

TIBET. Gyirong: Labi to Shale , 3100 m, 1 ix 1990, Li Bo-Sheng et al. 13373 ( PE 01486962 ). Nyalam : Qu Xian to Nielamu [Nyalam], 3400 m, 31 viii 1972, Tibet herbal medicine census 1659 ( HNWP;

PE 01187823 ); ibid., 3400 m, 1 ix 1981, Ni Zhi-Cheng et al. 1912 ( PE 00558352 ) ; ibid., 18 viii 2011, NN 5733 ( PE). Tingri : Da-ge-zhang, 4200 m, 29 vii 1959, Xizang exp. 676 ( PE 00935112 ) .

(5–7) Silene procera , S. nyalamensis and S. blepharicalyx

There are three similar Himalayan vicariant species, namely Silene procera , S. nyalamensis and S. blepharicalyx , that are distinguished from S. thomsonii by narrower leaves, shorter inflorescence branches and pedicels, and less deeply divided and narrower calyx. Differentiating characters are listed in Table 3.

Figures

Figure 3. Silene thomsonii: A, whole plant, low-altitude form; B, whole plant, Central Nepalese form to which the type of the name S. thomsonii belongs; C, whole plant, Central Nepalese form to which the type of the name S. thomsonii belongs; D, whole plant, eastern form from Solukhumbu; E, calyx (drawn from resoftened herbarium material; the calyces are much more closed when fresh, see Figure 4); F, calyx (drawn from resoftened herbarium material; the calyces are much more closed when fresh, see Figure 4); G, hairs on calyx teeth; H, hairs on calyx veins; I, upper part of pedicel; J, seed; K, seed; L, petal; M, petal. Scale bars: A–D, 10 cm; E, F, L, M, 1 cm; G–K, 1 mm. Vouchers: A, Suzuki et al. 9485253 (E); B, Hoshino et al. 9666181 (E); C, Yon 165 (E); D, Wakabayashi et al. 9710312 (E); E, Suzuki et al. 9485253 (E); F–H, B. Yon 233 (E); I, DNEP3 AY36 (E); J, Wakabayashi et al. 9710312 (E); K, KR 9740430 (KATH); L, B. Yon 233 (E); M, DNEP3 AY36 (E). Drawings: Magnus Lidén.

Figure 4. Silene thomsonii: A, eastern form; B, ‘weedy’ lowland form; C, widespread form (except the extreme east of the distribution area). Photographs: A and B, E. Byers; C, K. Halberg.