Scientific World, HMG / Nepal. Vol. 4, Number 4, July 2006 A Checklist of Trans-Himalayan Dicot Flora of Dolpo and Its Surrounding Region in Northwest Nepal Mani Raj Shrestha1, Maan B. Rokaya 1 and Suresh Kumar Ghimire2 For correspondence: 1G.P.box no. 15142, K.P.C. 319, Kathmandu, Nepal [email protected] / [email protected] 2 Central Department of Botany, Tribhuvan University. ABSTRACT Dolpo and Mustang lie in trans-Himalayan parts of Nepal. Present research revealed the phytogeographic uniqueness and floristic richness. Climatic barrier is the main cause of high endemicity, richness of flora, high aridity and rain shadow effect in the study area. A list of 1 forma, 14 varieties, 7 subspecies, and 312 species under 149 genera and 44 families of flowering plants of Dicotyledones were recorded from the trans-Himalayan area of northwest Nepal. Among the total species documented in the present study, 155 species were Himalayan endemic, and 18 Nepal endemic. Similarly 71, 36, 23, and 13 showed affinities with Southeast Chinese, Holarctic, Central Asiatic, and Eastern Asiatic regions. Key words: checklist, dicotyledonae, flora, phytogeography, trans-Himalaya. Collect (1921), DPR (1976, 1994), Grierson and Long (1983- INTRODUCTION 2001), Ohba and Malla (1988, 1991), Yamazi (1988); Noltie Since the botanical exploration in Nepal done by F. Buchanan- (1994- 2003), Polunin and Stainton (1984); Maheshwari Hamilton in 1802-03 the major floristic enumerations have (1997b); Ohba & Ikeada (1999) and Zhengyi & Raveen (1994- been focusing in central and eastern part of Nepal. Little 2001).They were crosschecked with the herbarium specimens attention has been given to the floristic study of western Nepal; deposited at KATH and TUCH. For collection of data related paticularly high altitudinal region. Thus, the present paper aims to origin of flora different literatures were consulted (Mani, to list the dicot flora of angiosperms in North-West part (Dolpo 1978; Dobremez et al., 1967-2003). The nomenclature given in and its surrounding Mustang region) of Nepal with special latest taxonomic literatures (Press et al., 2000; DPR, 2001) attention given to the trans- Himalayan arid areas. were adopted. The herbarium specimens are deposited at Tribhuvan University Central Herbarium (TUCH), Kirtipur, STUDY AREA Kathmandu, Nepal. The study area lies in between 28045’-29045’N latitude and 0 0 82 20’-83 45’E longitude covering part of upper Dolpa and upper Mustang in trans-Himalayan zone (Map 1). The area is arid as it is located at the rain shadow zone beyond the high mountain ridges formed by Mt. Dhaulagiri, Annapurna and Kanjiroba massive. The area is represented by its richness in alpine and arid flora with its phytogeographic uniqueness. The altitude ranges from 3600 to 6400 m above sea level. The study area represents sub-alpine, alpine to uppe-alpine type of vegetation with an altitudinal gradient of 3600-5600m. The trans-himalayan area is almost treeless and unexplored with arid ecosystem. Furthermore, it is considered as the most important sanctuaries of flowering as well as medicinal plants in western Nepal, and its ecological condition along with cultural virginity show it as the hidden paradise (Shakya, 1991; Ghimire et al., 2001 and Shrestha, 2004). The climate is similar to Tibetan Plateau with higher solar radiation and extremely low precipitation and it ranges from cool and humid to arctic and cold desertic types. Annual rainfall drops 250-500mm along the Tibetan borderland in western Nepal because of rain shadow and distance from the Bay of Bengal (Shrestha, 2004, Shrestha et al. 2005). MATERIALS AND METHOD Nepal The plant specimens of trans-Himalayan region include the collections done during two-field expeditions during different seasons in 2001-2003 and also some of the specimens collected by K. K. shrestha and S. K. Ghimire during 1996- 1997 and S. K. Ghimire 1997-2001. The collected specimens were throughly examined and identified by using relevant references as Hooker (1883-1887), Duthie (1903-1929), 1 Scientific World, HMG / Nepal. Vol. 4, Number 4, July 2006 Map 1: Map’s showing the trans-Himalayan parts of Dolpo and Origin & Distribution: Nepal Endemic. WCE Nepal (2100- Mustang region of Northwest Nepal (Source: Snellgroove, 4500m), Nepal. 1961) 2. Podophyllum L. 1. P. hexandrum Royle Moist meadows. Kunasa, 4100m, SM-457a (Dolpa). RESULTS AND DISCUSSION Origin & Distribution: Himalayan endemic. WCE Nepal The flora of the study area is comprised of a total 1 forma, 14 (3000-4500m), Afghanistan, Himalaya (Kashmir to Arunanchal varieties, 7 subspecies, and 312 species under 149 genera Pradesh), W. China. and 44 families of flowering plants of Dicotyledons (see Family 2. BIGNONIACEAE Checklist). 1. Incarvillea Juss. a. Family composition: In the present research Compositae 1. I. mairei (H. Lev.) Grierson was found to be the first largest family (37 species and 18 Open dry place. Siptyo, Dho, 4200m, SMDMN-197; Bag la to genera) and Ranunculaceae was the second largest family (30 Chunar (Malebagar), 4200m, SMDNL-366 (Dolpa). / 9); then followed by other families Leguminosae (21/ 10), Origin & distribution: South east Chinese. WC Nepal (3000- Cruciferae (18 / 13 ), Scrophulariaceae (18 / 8), Labaitae (16 / 4700m), Himalaya (Nepal, Bhutan), W China. 14 ), and Primulaceae (16 / 2 genera). The laregest genus recorded was Saxifraga with 14 species, followed by Primula Family 3. BORAGINACEAE (11), Pedicularis (10), Corydalis (7), Potentilla (7), Androsace 1. Arnebia Forssk. (6), Saussurea (6), Anemone (6), Delphinium (6) and Aster (5). 1. A. benthami (Wall. ex G. Don) I. M. Johnst The families followed by Genus and Species names are Grows on open slopes, shrubberies. Kunasa, 3900m, July arranged alphabetically in checklist given below. 1998 (fl), PPI97-206; Ribumba, Dho, 4200m, Maan-137 b. Phytogeography and origin of flora: The evolutionary (Dolpa). development and presence of mountains on all the continental Origin & Distribution: Himalayan endemic. W Nepal (2800- landmasses, and their climatic variations accordance with 4000m), Himalaya (Kashmir to Nepal). elevation affect the distribution of plants through its time of 2. Cyanoglossum L. origin. In the present paper, origins of flora have been 1. C. zeylanicum (Vahl. ex Hornem.) Thunb. ex Lehm., documented and are grouped under different categories. Out Cultivated areas, grazing grounds, wasteland. Jomesome, of 334 plant species, 155 species were Himalayan endemic 3000m, SMDMN-11 (Mustang). and 18 were Nepal endemic. Similarly, 71 species showed Origin & Distribution: Sino-Japanese-Indo-Malaysian. WCE affinity with South East Chinese region, 36 with Holarctic, 23 Nepal (1200-4100m), Afghanistan, Himalaya (Kashmir to with Central Asiatic, 14 with Sino-Japanese or Eastern Asiatic, Bhutan), India, Sri Lanka, east to China and Japan, Malaysia. 5 with Tibetan, and Indian, Sino-Japanese-Indo-Malaysian East Asiatic-Malaysian, Tropical, Western Asiatic region each 3. Eritrichium Schrad. boelongs to two species respectively. Two species were 1. E. cannum (Benth.) Kitam. introduced or cultivated. The result showed that the study area Rocky dry meadows. Dho to Num la Phedi, 4300m, SMDMN- is highly influenced by South East Chinese region. Tibetan 250 (Dolpa) elements are also profoundly found in the northern side of Origin & Distribution: Himalayan endemic. WC Nepal trans-Himalayan flora. (3800-4600m), Afghanistan, Himalaya (Kashmir to Nepal), China (S Tibet-Xizang) c. New addition to the Flora of Nepal: In the present study 2 4. Hackelia Opiz. genera, 3 varieties, 3 subspecies and 12 species were 1. H. uncinata (Benth.) Fisch. recorded as new addition to the flora of Nepal. Besides, 70 Shrub land. Way to Punikha, 3800m, SM-529 (Dolpa). species were recorded as new addition to the Flora of Origin & Distribution: South east Chinese. WCE Nepal Northwest Nepal and 84 species were recorded as new within (2700-4200m), Himalaya (Kashmir to Bhutan), NE India and beyond their range of vertical distribution. These species (Assam), China (Xizang, Yunnan). are marked by astrik (*) and bold number in altitude and single letter in distribution in the checklist given below. 5. Lindelofia Lehm. *1. L. anchusoides (Lindl.) Lehm. Checklist of Trans-Himalayan Dicot flora of Northwestern Nepal Open dry place.Thujekarma to Juniperus forest base camp Family 1. BERBERIDACEAE (Sandak valley), 4000m, SMDMN-82 (Mustang). Origin & Distribution: Centrasiatic. W Nepal (4000m) NE 1. Berberis L. Afghanistan, Himalaya (Kashmir to Himanchal Pradesh). 1. B. angulosa Wall. ex Hook. f. & Thomson, *2. L. stylosa (Kar. & Kir.) Brand in Engler Shrubland. Pugmo, 4300 m, PPI97-95 (Dolpa). Rocky slopes. Dho to Num la Phedi, 4200m, SMDN- 247 Origin & Distribution: Himalaya endemic. CE Nepal (3400- (Dolpa). 4500m). Himalaya (Nepal, Sikkim), NE India, China (SE Tibet, Origin & Distribution: Centrasiatic. W Nepal (4200m), Xizang). Afghanistan, Kyrgyzstan, Himalaya (Kashmir, Himanchal 2. B. lycium Royle Pradesh to Nepal), Mongolia, China (C & W Gansu, NW Moist shrub land. Ruktang, 3000m (fl), PPI97-65 (Dolpa) Xizang). Origin & Distribution: Himalayan endemic. WCE Nepal (1800-2900m). NE Afghanistan Himalaya (Kashmir to Nepal). 6. Microula Benth. 3. B. mucrifolia Ahrendt, 1. M. sikkimensis (C.B. Clarke) Hemsl. Dry place. Dho, 4200m, Maan-115 (Dolpa). 2 Scientific World, HMG / Nepal. Vol. 4, Number 4, July 2006 Moist and dry shrub land. Juniperus forest base camp (Sandak 3. C. lobatus Wall. ex Benth. Valley), 3800m, SMDMAN-96 (Mustang);