O U T L I N E OF N E P A L P H Y T O G E O G R A P H Y

by

M. L. BANERJI , Kalyani (India)

During the last io years interest on the study of Nepal flora seems to have increased very much. Besides the British Museum, Japanese Botanists, and the author, who have had planned explorations of the areas of their interest and which extended over a number of years, there have been others who have also taken interest on the flora of Nepal. V. PuRI was an Indian Government nominee to the British Museum expedition to West Nepal in 1953 ; the Daily Mail "Yet i" expedition of 1955 and 1956 also had members (STONER and BACI-IKETHI) who have collected plants, and finally the Indian Mt. Cho-Yo expedition of 1959 had R. S. RAo with them. But information about these collections is yet too meagre, as no publication has appeared SO f a r .

The extensive collections made from East Nepal by ZlMM~RMANN during the 1952 and 1954 Swiss Mt. Everest Expeditions is being worked out and information is appearing in regular instahnents in "Candollea"; this publi- cation affords much valuable information about the plants of the area, besides the Journal of the Royal Horticultural Society (Vols. 75, 78, 79 & 80).

BUI~KInL (191o) wrote "it is ill gleaning for novelties after a botanist with the keenness of Wallich; so I got no more than three species of Im- joatients and apparently one E, rioeaulon". But a number os new taxa have been described from Nepal in very recent years. KITAMURA (I955) has added 30 species and 15 vars. and forms of dicotyledons, and another 3 species of monocotyledons. From the collections made by the personnel of the British Museum (PoLuNIN, STAINTON, SYKES and WILLIAMS) during the years 1949-1954, there have been added a number of Saxifragas (SMITI~ 1958 & 196o), 4 spp. of Taraxacum (VAN SOEST 1961), 3 spp. of Saussurea (LuDLow 1956), and 3 spp. of Pedicularis (TsooNG 1955). Some new Rhodo- dendrons have also been added by DAVlDIAN (1951--56). BANeRJI (1951 & 195 z) has described i sp. and 5 vats. also. The Swiss botanists, so far, have also described a number of new taxa (see Candollea Vol. 15 to 18). But a special mention should be made of the genus Mecon@sis and of Primula. There have been added 7 species of Mecon@sis- M.regia; M.bdla; M.dhowjii; M.longipetiolata; M.grandis; and M.discigera. Nepal has also been found to be rich in Primulas, and the new species recently described are P.didyma; P.wigramiana; P.ramzanea; P.nepalensis; and P.redii var. williamsii; as also in Saxifraga of which 19 species have been described (SMITH 1oc.cit.).

A brief analysis of the data that has gradually accumulated may be made. A census of the number of the genera of some of the prominent polypeta- lous families is as follows:

Ranunculaceae 14 genera. Cruciferae 15 genera. Caryophyllaceae io ,, Malvaceae 5 ,, Rutaceae 5 ,, Ampelidaceae 6 ,, Leguminoseae 4 4 ,, Rosaceae 22 , ,

Saxifragaceae io ,, Cucurbitaceae 9 ,, Umbelliferae 16 ,,

Received 1963

ON NEPAL PHYTOGEOGRAPHY 289

I. Species found in Eastern N e p a l

(a) East Himalayan elements : Berberis bhutanensis AHRENDT; Menocopsis horridula var. typica PRAIN; Cardamine trifoliata HH~z.f. & TI-I.; Stellaria sikki- mends HK.f. ; Impatiens arguta HK.s I. faMfer HK.f. ; Acer campbellii HK.f. ex Hiern; A. papilio KING; A. sikkimensis MIQ. ; Ribesgriffithii HK.f. & TI4. ; Saxifraga nutans HK.f. & TH.; Cortia hookerii C.B.CL.; Pimpinella clarkeana WATT ex BANERJI; P. sikkimensis C.B.CL.; Lactuca macrantha C.B.CL.; An- drosace croftii WATT. ; Primula aequalis CRAIB. ; P. boothii CRAIB. ; P.con'cinna WATT. ; P. filipes WATT. ; P. g]abra KLATT. ; P. listeri KING. ; Symplocos caudata WALL. ex DC. ; S. dryophy]a C.B.CL. ; S. flyrifolia WALL. ; S. suman- tia BUCH.-HAM. ; Trachdospermum axillare H~z.f.; Cinnamonum impressinervum MEISSN.; C. parthenoxylom MErSSN.; Salix daltoniana ANDRS.; S. sikkimensis ANDRS.

(b) West Himalayan elements : Braya alpina STERNB. & HOm'E,; Stellaria webbiana EDGBW.; Sagerettia oppositifolia BRO~G.; Rhus wallichii HK.s Cynanthus microphyllus EDGEW. ; Campanula sylvatica WALL. ; C. argyrotricha WALL.; Swertia purpurascens WALL.; Prinsepia uti/is RoYLF.; Herminium gramineum LI>mL.; Luisia trichorhiza BL.

2. Species found in Western N e p a l

(a) West Himalayan elements : Syringia emodi WiLn.ex G.DoN. ; Olea glandulifera WALL. ex DC.; Ligustrum compactum HK.s & TH.; Gentiana squarrosa LEsmu.; Swertia paniculata WALL.; Alazus hermandi BONATI,; Pedi- cularis hoffmeisteri KLOTSCH,; P. hookeriana WALL.; Picrorrhiza scrophulariae- folia PF.NNEL. ; Serophularia decomposita ROYLE,; PlaXystemma violoides WALL. ; Scuttdlaria grossa WALL.; Phdomis spectabilis FaLc. ex BENTH.; Lamium album Li>rs.; Elsholtzia densa BENTH.; Aspergo procumbens LINN. ; Cyri- pedium cordigerum D. DON; Platanthera galeandra RmcHu. f.; Hemipdia cordi- folia LINDL. ; and many others.

(b) East Himalayan elements : Meconopsis nepalensis DC. ; Viola distans WALL.; Kydia glabrescence MASTERS,; Eryobotrya dliptica LINDL.; Prunus rufa WALL.; tgoma]ium nepalensis WALL.; Brassiopsis hain]a SEEMS.; Embdia undulata MEZ. ; Exacum teres WALL. ; Symplocos thaefdia HA~a. ex DON. ; Clerodendron colebrookianum WaLl,.; Veronica klozii PEru,mE.; Scrophularia pauciflora BENTH.; S. urticefolia BENTH.; E/atostemma rupestris WEDD.; Dio- scorea sikkimensis PRAIN & BURKILL, and a few others.

Botanically Nepal is of particular interest, for it is here that the differing floras os the Eastern Himalaya and the Western Himalaya merge. In East Nepal, the late Sir W. W. SMITH (private communication) expected some 9o% of east himalayan species. ]3URKILL on an analysis of his own collec- tions made in the central part os Nepal found 28 eastern himalayan species and 4 western himalayan species.

HOOKER divided his Himalayan botanical region into two botanical provinces: The Western and the Eastern. The Western Himalaya was defined by HOOKER as extending from Kumaon to Chitral; and the Eastern Himalaya as extending from Sikkim to the Mishmi Hills in Upper Assam. Due to paucity of information about the flora of Nepal, HOOKER had left out of account the kingdom of Nepal which extends for about 840 kilometers Vegetatio, XI, 5-6. i9

290 iVI. L. B A N E R J I

(5 z5 miles) between the Eastern and Western Himalaya as defined by him. The general characters of the Eastern Himalayan flora were deduced by HOOICER from the study of the flora of Sikkim and a little of the adjacent part of eastern Nepal which were then botanically well known, and he had himself visited these places in 1848 and 1849. Too scanty information was available about the flora of Bhutan and Western China. Similarly the range of extension of the Sino-Himalayan elements into Nepal was very poorly known. In 194o CHATTERJEE had some more information about the flora of Nepal, also about the range of extension of the Sino-Himalayan elements into Nepal than what was known to HOOKER. Thus, CHATTERJEE dis- tinguished it as the Central Himalayan botanical province.

A brief perusal of the general distribution in Nepal is necessary. The rang- es that run north to south (NNE to SSW) in East Nepal stand as natural barriers in the distribution of a number of species, particularly those of Rhododendron (see graph) BANERJI 1954)and os family Vacciniaceae. The

T A B L E I

D I S T R I B U T I O N O F S O M E S A X I F R A G A S I N T H E H I M A L A Y A .

~ame of the species

I. Saxifraga georgei S. andersonii S. glabricaulis S. contraria S. granulis S. sphaeradena

s. sp. sphaeradena S. stella-aurea

var. polyadena S. lepida

K. S. pulvinaria

II. S. kumaunensis

V. S. roytei S. alpigena S. will iamsii S. lowndesi i S. mira S. poluniniana S. s taintonii S. rhodopetala S. micans S. cinerea S. zimmermarlii S. sphaerader, a

s. sp. dhowji

V. S. afghanica

K PH ICH

O ' ~

~t3

N H

_ o

~9

O

O9 - = - - o

- g,

SH B SET

K - - Kashmir ; PH - - Punjab Himalaya; K H - - Kumaon Himalaya; N H - - Nepal Hi- malaya; SH - -S ikk im Himalaya; B - - Bhutan; and SET - - South-east Tibet. The Nepal Himalaya is divided into three sections.

ON NEPAL PHYTOGEOGRAPHY 291

family Vacciniaceae is wel l represented in Eas t e rn Himalaya , and in Eas t Nepal there are the same 5 species m e n t i o n e d by SMrT~I (I913) for South East S ikkim - - such as Agajoetes serpens (WIGHT) SLEUMER, (syn. Pentaplery- glum serjoens (WmHT)KJ~oTz.); Vaccinium nummularia HK.f. & TH. ; V.serra- turn WIGHT; V. retusum HK.f . ; and V. dunalianum Wm HT, and in add i t ion to these there is also Agapetes incurvata (Ge, zFF.)SLEugER vat . hookerii (C.B.CL.)AIRY SHAW, (syn. A hookerii (C.B.CL.)SL~uMER,). F u r t h e r west- wards, there is a g radua l r e d u c t i o n o f the species and KZ'rA~URA (1955) records on ly one species - - Vaccinum retusum f r o m Wes t Nepal .

Acco rd ing to PENNeL (I943) the d i s t r i bu t ion of the genus Pedicularis is equal ly in teres t ing. There are T 9 species that be long to Wes t e rn Himalaya ; o f these there are 7 species that ex tend f rom Nepal westwards to K u m a o n and fur ther west , 6 species extend all a long the l eng th o f the Himalaya .

T A B L E IL

D I S T R I B U T I O N OF T H E G E N U S SWERTIA IN T H E HIMALAYAS.

Name of the species K PH KH NH

I. Swertia cuneata S. pulchetla S. angustifolia S. cordata S. chirata

II. S. petiolata S. thomsoni

III. S. tetragona S. coerulea

IV. S. speciosa S. alata S. purpurascens S. lurida S. altemifolia

V. S. paniculata

VL S. racemosa

VII. S. dilatata S. nelwosa S. multicaulis

VIII. S. hookerii S. rex

IX. S. bimacnlata S. griffithi

~ o

- - = .~ "=~

. . . . . . . . . . . ~ =~ . . . .

8

-?

-?

? ? . . . . . . . ? ? . . . . . . .

SH I B

K - - Kashmir; P H - - Punjab Himalaya; K H - - Kumaon Himalaya; N H - - N e p a l Hi- malaya; S H - - Sikkim Himalaya; and B - - Bhutan; The Nepal Himalaya is divided into three sections, and the extension of the distribution of any species in any section which is still unknown is represented by a mark '?'.

x9*

a92 M.L. BANERJI

Recently TSOONG (Ioc.cit.) worked on the Pedicularis collection of the British Museum, and he has mentioned 6 species to be restricted to Nepal, ,z species that extend from Nepal to Bhutan and also S.E.Tibet. According to BoR (I953) the species of Salix found in India fall into two natural groups: those which are found in the North-Western Himalaya and those found in the Eastern Himalaya. Salix daltoniana and S. sikkimensis which are Eastern Himalayan species extend westwards to Nepal, and probably only upto Eastern Nepal, and S. elegans and S. wallichiana which are North-western Himalayan species extend eastwards and reach Eastern Nepal. Equally interesting is the distribution of the Saxifragas (Table I) and Swertias(Table II) along the Himalayan range. As regards the genus Allium's distribution, STEARN (I960) finds that A.stracheyii is a species that is confined to the Western Himalaya including Western Nepal; A. pratii and A. wallichii are species of the western China that extending from Yunnan along the eastern Himalaya over much of Nepal extend into Kumaon Himalaya. A . fasci- culatum is a species of the dry plateau zone of Tibet and extends into the dry zones of Sikkim and Nepal. No Allium is so far reported to be only confined to Nepal. Study of the genus Allium confirms the impression given by the other genera that the flora of Bhutan is closely linked to and partly con- specific with the flora of Western China and that Nepal is a meeting place of the Eastern and Western Himalayan floras.

It may also be noted that Cedrus deodara reaches its easternmost known station at 8z~ ' E., while Magnolia campbellii, on the other hand, reaches its westernmost known station at 83~ ' E, and Gentiana depressa at 84 ~ E. Cyathea spinulosa has been collected 86038' E.; although this taxa was originally described from Nepal, the limits of this species are disputed.

BURRARD 6r HAYDEN (1907) and later K. MASON (1934 & I9J 5) have partitioned the Himalaya into divisions convenient for general purposes: from west to east they are (i) The Punjab Himalaya (between the Indus and the Sutlej); (z) The Kumaon Himalaya (extending east of Sutlej to the Kali which also forms the western boundary of Nepal); (3) The Nepal Himalaya (with 3 sub-divisions); and (4) The Sikkim Himalaya and the Assam Hima- laya (mostly Bhutan etc. upto Brahmaputra).

For botanical purposes the Nepal Himalaya may be divided into three sub-divisions approximating to MASON'S thought- e.g. Western Nepal, Central Nepal and Eastern Nepal. Because of Nepal's importance as an area of "transition" or we may also call it as an area of merging, these divisions are very necessary and the present author has followed this scheme of division in his work on the flora os East Nepal. Most recently ST~ARN (Ioc. cit.) has also used these divisions in his work on Allium and Milula ot Central and Eastern Himalaya, and he has further suggested some modifi- cations to MASON'S thought about the divisions of Nepal. Thus it may be given as: (also see Map)

I. Western Nepal (From the Kumaon frontier to 83 ~ E. - - correspond- ing to MASON'S Karnali section).

II. Central Nepal (83~ to 86~ - - corresponding to MASON'S Gan- daki Section which is from Dhaulagiri to Kathmandu i.e. 8z~ to 85~

III. Eastern Nepal (86~ to Sikkim frontier - - corresponding to MASON'S Kosi section).

29

i A

o z Z "d

294 M.L. BANERJI

~ , , , , , ,

/;,~j 0001,,

IO, 0oo~

,.~', oo o / .

West NEPAL

i -Co... 4,,r :,'~,.

- c , ~ . . 3 o 4 , ~ ~,'a,.

�9 " - ~ . . / a - a & "m,. ~

L

, i

Central NEPAL ', East NEPAL Sikkim (Height of ranges at ca 27o30 , N)

The author is in complete agreement with STEARN in this scheme of division and also holds that on generalgrounds, longitude 83~ may be taken as the bouzldary between Western Himalaya and Eastern Himalaya, and Ct-IATTEI~JEB'S Central Himalayan botanical province is thus ruled out as it is unsupported by present phytogeographical evidences. It is indeed a convenient political concept as also geological. With further careful study and plotting of geographical positions, we shall have still more substantial and convincing grounds for the deductions. It is strongly advocated that for the study of the flora of such "transition" areas or "merging" areas, mapping the ranges and distribution of species is very necessary, a point that has been already emphasised by TtrRRII. (1954).

It will be quite pertinent to mention here that if for practical purposes and for better understanding of distribution and extension os species the divi- sions of Nepal as made above, are followed, then the Japanese botanists and some of the explorations of the British Museum have been made in Central Nepal.

ON NEPAL PHYTOGEOGRAPHY z95

S U M M A R Y

Dur ing the last decade many have been interested in the study of the flora of Nepal. There have been those who have carried their investigations over years and others who have visited only once, but all have brought Valuable information about the distr ibution of plants in the area.

In recent years, Nepal has p roved to be rich in new taxa and particularly in the new species of Meconopsis, of Primula and of Pedicularis. Based on the published data, some deductions can be made about the phytogeography of Nepal. Informat ion is gradually accumulating and becoming available as to the range o f extension o f the widely accepted East Himalayan elements and the West Himalayan dements . It is here in Nepal that the differing floras o f the Eastern and Western Himalayas merge. The outstanding result is an expression of the eastern-ness of the vegetat ion of East Nepal, while in West Nepal the West Himalayan elements abound; thus botanically Nepal is of particular interest.

Because o f Nepal 's importance as an area of " t rans i t ion" or as we may also call it as an area of " m e r g i n g " , the geographical subdivisions of Nepal are discussed in the paper. Further , the data at hand is now much more than what was available to HOOKER and CHaTT~RJEE. The author, in complete agreement with SrEARN, proposes that lang: 83~ may be taken as the boundary between the botanical provinces of Eastern Himalaya and Western Himalaya. It is also pointed out that in the study of the vegetat ion of such areas where differing floras meet, p lot t ing o f geographical positions is a necessity.

L I T E R A T U R E C I T E D

AtSTO>~, A. H. G. & C. IS. B. BONNEt, I956 - - R6sultats des Exp6ditions Scientifiques Genevoises Au Nepal in 195 z et 1954 (Pattie Botanique) 5-Pteridophyta. Candollea 15, 193-22o.

BANERJI, a . L., I95I - - Two new species of Pimpinella.J. Born. Nat. Hist. Soc. 50, 88-90. BaNERJZ, M. L., I95z - - Some noteworthy plants from East Nepal.J. Indian hot. Soc. 31,

I5z-I53. BANERJI, M. L., I954 - - Note on the distribution of Rhododendrons in Nepal. Science &

CMA ao, 9z-93 . CHATTERJEE, D., I94o - - Studies on the endemic flora of India & Burma.J. Roy. Asiat.

Soc. Bengal 5, '9-67 �9 DavmiaN, H. H., I965 - - New Rhododendrons from Nepal. Notes from the Roy. Bot. Gard.

Edin. 2i, 99. BURKILL, L H., I9Io - - Notes from a journey to Nepal Rec. Bot. Sum. India. 4, 59-I4o. B oR, N. L., 1953 - - Manual of Indian Forest Botany. Calcutta. BURRaRD, S. G. & H. H. HAYDeN, 1907 - - A sketch of the Geography and Geology of

the Himalaya Mountains and Tibet. Calcutta. Hoo~R, J. D., 19o6 - - A sketch of the flora of British India. Imperial Gazetter (ed. 3.)

Oxford. Km,~Ra, H., 1955 - - Fauna and Flora of Nepal Himalaya. Kyoto. K~:ra~auRA, S., 1955 - - In Kihara's Fauna and Flora of Nepal Himalaya. Kyolo. LuDLow, 1956 - - In Novitates Himalaicae I. Bull. Brit. Mus. @4at. Hist.) BoA 2(3), 67-8L MASON, K., 1934 - - A note on the Nepal Himalayas. The HimalayanJ. 6, 81-9o. MasoN, K., 1955 - - Abode of Snow. A History of Himalayan Exploration and Moun-

taineering. London. PEN>a~LL, F. W., 1943 - - The Scrophulariaceae of the Western Himalayas. Acad. dVat. Sci.

Phila A~onogr. 5. POLUNIN, O., I95o - - An expedition to Nepal._/. t~oy. hort. Soc. 75, 3o4-315-

296 M. L. BANERJI

SANTAVAU, H. et aL I958 - - Additions and corrections to the Indo-Nepalese flora. Proc. ~Xgat. Inst. Sci. India. 24, I33=I39.

SMITH, H., 1958 - - Saxifraga of the Himalaya-I; section Kabschia. Bull. Brit. Mus. (Nat. Hist.) Bot. 2(4), 85-I29.

SMITH, H., I96o - - Saxifraga of the Himalaya-II; some new species. Bull. Brit. Mus. (Nat. Hist.) Bot. 2(9), 229-260.

SMITH, W. W., I9I 3 - - The alpine and subalpine vegetation o f southeast Sikkim. Rec. Bot. Sum. India, 4, 323-43 L

STEARN, W. T., i96o - - Allium and Milula in the Central and Eastern Himalaya. Bull. Mus. (Nat. Hist.) Bot. 2(6), I6I-I9 I.

TSOONG, P. C., 1955 - - New Himalayan species o f Pedicularis. Bull. Brit. Mus. (Nat. Hist.) Bot. 2(I), 1-34.

Tso-TsuN, YI., I954 - - Cotoneasters from the Eastern Himalayas. Bull. Brit. Mus. (Nat. Hist.) Bot. I, I25-I4I.

Tuluti t , W. B., I954 - - Mapping the ranges and distribution of Taxonomic groups o f plants. Kew Bull.. i945, 59-64

VAN SO,ST, J. L., I96t - - New species o f Taraxacum from the Himalayan region. BMI. Brit. Mus. (Nat. Hist.) Bot. 2(xo), 263-273.

WILLIA~aS, L. H. J., x953 - - The i952 Expedition to Western Nepal .J . Roy. hort. Soc. 78, 323-337 �9