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— FLORA OF PUNJAB STATE A PHYTOGEOGRAPHIC ASSESSMENT 1 M. Sharma and Kusum Rajpal2 (With a text-figure) Key words: phytogeography, flora, Punjab A phytogeographic analysis has been made of 1,119 spermatophytes recorded from Punjab State (India). The floralelementsofitstwowell-markedfloristicsubunitshavebeencomparedand possiblereasonsgivenforthedistribution offloral elements. Fourbroadclasses offloral elements have been distinguished. The Indianelement isratherpoor. The eastern elementalmostequals the westernelement which showsthattheareaisameetingground forthesetwotypes of elements. The general element is the most conspicuous and includes species ofcosmopolitan, tropical and temperate distribution.TheStateiscategorizedasatransition zone fromthewarmandhighseasonal rainfall tropical areasofSouth- EastAsiatothesemi-arid MiddleEasterncountriescharacterizedbycolderwinterandabsenceofanymonsoon influence. Introduction With the aim of writing an up-to-date flora of Punjab State (India), the senior author has been engaged uninterruptedly in its floristic survey eversince July 1963. Bibliographic reference to sixtythree publications that ensued will be found in Sharma (1990). Hitherto, no phytogeographic studies have been made on the flora ofPunjab State. The present paper covers this aspect and also makes a comparison of the floral elements of its two well- marked floristic subunits, namely semi-arid Punjab and Punjab Shivaliks vis-a-vis the whole ofPunjab State. General features of the area The present Punjab State (India) lies between 29° 30' and 32° 32’ N lat. and 73°54' and 76°50’ E long, and covers an area of 50,362 sq.km (Fig. 1 ). Within it; three floristic subunits, namely (1) semi- arid Punjab (mainly southern part), (2) moisterplain country (central part) and (3) Shivaliks (north- eastern hilly tract) can be recognized. The first and Fig. 1. SketchmapofPunjab State(India)showingits floristic subunits. third subunits are not only two disjunct zones but also show difference in topography and climate and hand, has a mixed or the general flora of the State. Height above m.s.l. of the three zones respectively are characterized by their distinctive floral elements. m The intermediate moister plain country, on the other varies between 205-230m, 230-300 and 300-800 m; whereas average annual rainfall is 43 cm, 60 ‘AcceptedJanuary 1991. cm and 90 cm in corresponding tracts. The winters departmentofBotany,PunjabiUniversity, Patiala-147002, India. are intensely cold and summers extremely hot. The — FLORA OFPUNJABSTATE A PHYTOGEOGRAPHICASSESSMENT 161 minimum temperature (-2.8°C) was recorded at Tabie 1 Amritsar on 24th January 1989 and maximum ANALYSIS OFMAJOR PHYTOGEOGRAPHICREGIONS (49°C) at Bathinda on 26-28th May 1984. OFTHEFLORA OFPUNJAB STATE Material and methods No. Region No. of Percentage Species Based upon the plant collections made by the present senior writer fornearly 25 years (1963-1987) 1. Endemic 3 0.27 from Punjab State, study of pertinent herbarium 2. India 83 7.42 specimens at BSD, DD, PAN and PUN, and the 3. Indo- Malaya 263 23.51 4. North Africa-Indian relevant information scattered in literature; a check- Desert(Saharo-Sindian) 106 9.47 list of the vascular plants of Punjab (Sharma 1990) 5. Tropical andNorthAfrican- was published. The list includes 1,879 species out Indian Desert(Sudano-Deccanian) 50 4.47 ofwhich 1,119 wild and naturalized spermatophytes 6. Tropical Africa- India 43 3.84 7. TropicsoftheOldWorld 209 18.68 have been taken into account and form the basis for 8. Pantropical 114 10.19 the present communication. To avoid cumbersome 9. Warmcountries 13 1.16 terminology of several authors in which the areas 10. Subtropical andtemperate 7 0.62 of distribution may have somewhat different 11. Mediterranean 22 1.97 connotations, the regions as presently recognized 12. Orient 11 0.98 13. Europe 62 5.54 are practically the same as listed by Bharucha and 14. Cosmopolitan 30 2.68 Meher-Homji (1965). The possible route(s) and 15. Americas 53 4.73 means of migration have been discussed and 16. Himalaya 31 2.77 illustrated in detail by Chatterjee (1939, 1947), 17. Temperate 19 1.70 Maheshwari (1962, 1979) and Singh (1978). The Total 1119 100.00 observations by these authors are equally applicable to the floral elements of Punjab also and hence substratum. More recently, however, anthropogenic these two aspects have been excluded from the disturbances have altered these patterns to some purview of discussion. extent. The discussion below pertains to the floral Results elements ofthe fourmain classes as grouped in Table 2 and compared in Table 3. The analysis of major phytogeographic regions ofthe flora ofPunjab State is given in Table The Indian element: It is rather poorly 1 . The floral elements of these regions have been represented in all the three floral regions (Table 3). The extreme climatic conditions and dry, sandy broadly grouped into 4 main classes (Table 2) taking substratum appear to be the barriers to the into account the fact that it is not always possible to establishment of the Indian element. Chatterjee assign a species precisely to one group or the other particularly in those cases where the species are (1939) has listed 134 dicot genera endemic to India. A Out of these; only few like Ougeinia Benth., Butea widely separated. generalized view has been taken Wiild., Caesulia Roxb., Glossocardia Cass, and in such cases. Comparative analysis of the floral AechmantheraNees occur in Punjab. There are only element classes ofthe different floristic subunits of three endemic species in the flora of Punjab State, Punjab State has been given in Table 3. namely Hibiscus hoshiarpurensis Paul and Nayar, Discussion Argyrolobium album Bhattacharyya and Rumex The flora of Punjab State shows four punjabensis Vaid and Naithani. The first two of distinguishable patterns. These patterns (type of these have been reported fror Punjab Shivaliks. m elements) have been shaped by the coincidence of There is no endemic species the flora of semi- historical events, topography, climate and arid Punjab. It is interesting to note that Indian . 162 JOURNAL BOMBAYNATURALHIST.SOCIETY. Vol. 92(1995) Table2 appears to be a chance introduction because only ANALYSIS OFTHEFLORALELEMENTCLASSES OFTHE two specimens have been gathered from this area. FLORA OFPUNJAB STATE The absence of the Himalayan element from the No. Floral element No. of % semi-arid Punjab can be easily explained because Species of the discontinuity of Punjab Shivaliks with this zone, besides the difference in the edapho-climatic 1. Indian 117 10.46 (a) Endemic(1)* features of the two areas. (b) Indian (2)* The Eastern element: The percentage of (c) Himalayan ( 16)* Eastern or Indo-Malayan element is nearly double 2. Eastern(3)* 263 23.51 than that of Indian element. These species are the (Indo-Malayan) 3. Western 294 26.27 denizens of humid climate and their occurrence is (a) N. African-Indian Desert (4)* as high as 53% in a humid region like that ofBengal (Saharo-Sindian) (Agharkar and Ghose 1931). These cannot tolerate (b) Tropical and the dry and semi-arid conditions as prevailing in N. African-Indian Desert(5)* A (Sudano-Deccanian) our area. study of the floral elements in relation (c) Tropical African - Indian (6)* to climate reveals that as there is an increase in the (d) Mediterranean-Oriental- rainfall and decrease in temperature from south European (11, 12, 13)* 4. General 445 39.76 towards north Punjab, there is a marked increase in (a) Tropical (7,8, 10, 15)* the number of eastern element. This is proved by (b) Warmcountries (9)* the fact that the eastern element constitutes only (c) Temperate (17)* 12.42% of the flora of semi-arid Punjab, whereas it (d) Cosmopolitan (14)* contributes 28.83% in the flora of Punjab Shivaliks Total 1119 100.00 where the climatic conditions are somewhat moderate in comparison to those of semi-arid * Numbers within parenthesescorrespondtotheNo. of Table 1 Punjab. Conversely, the western element (cf. Table element preponderates in the semi-arid Punjab in 3) is much pronounced in the southern side (semi- comparison to the flora of Punjab Shivaliks. The arid Punjab) than in Shivaliks. The present studies Himalayan element is almost totally lacking from fully support the conclusion arrived at by Legris and the semi-arid Punjab. Saussurea heteromalla Hand.- Meher-Homji (1968) that the Indo-Malayan and the Mazz. has been recorded from this tract which Indian elements are represented a little in the dry, Table3 COMPARATIVEANALYSIS OFTHEFLORALELEMENTCLASSES OFTHEDIFFERENTFLORISTIC REGIONS/ SUBUNITS OFPUNJAB STATE Floralelement Punjab State Punjab Shivaliks Semi-arid Punjab (presentwork) (presentwork) (Sharmaetal. 1987) No. of Percentage No. of Percentage No. of Percentage species species species 1. Indian 117 10.46 75 12.36 47 9.89 2. Eastern 263 23.51 175 28.83 59 12.42 3. Western 294 26.27 99 16.32 145 30.54 4. General 445 39.76 258 42.49 224 47.15 Total 1119 100.00 607 100.00 475 100.00 — FLORA OFPUNJABSTATE A PHYTOGEOGRAPHICASSESSMENT 163 thorny series of Capparis-Acacia and Salvadora - Bacopa monnieri Penn., Ceratophyllum demersum Prosopis vegetation, so characteristic of semi-arid Linn.,EleocharispalustrisR. Br.,Lemnaperpusilla Punjab. Torr., Spirodela polyrhiza Schleid., Scirpus The Western element: It is fairly well maritimus Linn., Veronica anagallis - aquatica represented in the flora ofPunjab State.—It comprises Linn, and Zannichellia palustris Linn. The wide of the African and Mediterranean Oriental- distribution ofaquatic plants is perhaps due to their European species. The African element (67.68%) dispersal by migratory birds. Besides, an aquatic in the flora of Punjab State is much more than the habitat constitutes a most homogeneous medium. rest of the element of this class. This is probably Other cosmopolitan species like Chenopodium because of the similar climatic conditions in Africa album Linn., C. murale Linn., Cleome viscosa and present area. The distribution of this element Linn., Convolvulus arvensis Linn., Coronopus is governed by high temperature and comparatively didymusLinn., Poa annuaLinn., Setaria verticillata low rainfall as experienced in Punjab State. Further, P. Beauv., Solanum nigrum Linn., Sonchus asper there is no effective barrier on the western boundary Hill, S. oleraceus Linn., Xanthium strumarium of India to check the migration of xerophytic Linn., etc. are aggressive weeds. Temperate element elements of Afro-Arabian origin which may enter is very meagre andrepresented by 1.70% ofthe flora. through Rajasthan or Pakistan. Mediterranean- This is to be expected because of the extremely hot Oriental-European element though not as plentiful climate in the area during summer and monsoon as the African element yet is well represented months. (32.32%) in the floraofPunjab State. The low winter The occurrence of so many types of floral temperature prevailing in Punjab may account for elements in Punjab State or its subunits like Shivalik the introduction of this element. The north-west hills or semi-arid region is interesting. The area India, according to Gaussen (1933), forms a part of has a very dry type ofclimate with a long dry season the mediterranean region. Adventive taxaofwestern of about 9- 0 months alternating with a very short 1 origin which have recently established themselves and erratic rainy season (July-September). Summers in Punjab include Hypecoum pendulum Linn., are very hot with the mean minimum and maximum Sagina apetala Ard., Oxalis pes-caprae Linn., temperatures during May-June being about 15°C Trifolium tomentosum Linn., Urtica urens Linn., and 43°C respectively. On the other extreme, winters Eribchloa nubica Thell., Lophochloa pumila Bor, are severe. The mean maximum and minimum Panicum maximum Jacq., etc. According to Legris temperatures during the colder months (December- and Meher-Homji (1968) this element exceeds but January) are c.20°C and c. 10°C respectively. little the limit of winter range and it does not Besides, there are also conspicuous alternations in penetrate deeply into the Indian peninsula. the hours of the day length during summer and The General element: It is by far the most winter. The overlapping of several floral elements conspicuous and includes, besides the cosmopolitan seems to be due to these seasonal changes in the element, the temperate and tropical species also. climate. While the Indian element has practically The tropical element much exceeds the flora ofany the same percentage in Punjab State, Punjab othertype here. The temperate element is very poorly Shivaliks and semi-arid Punjab, the proportion of represented because of the inclusion of semi-arid Indo-Malayan element is more than double in the tract in the area and extremely hot climate during flora ofPunjab Shivaliks in comparison to the flora summer and monsoon months. The cosmopolitan of semi-arid Punjab. This is because the Indo- species are either naturalized from cultivation Malayan element generally develops during (Brassica campestris Linn, vars., Raphanus sativus monsoon period and seeks shelter in humid sites. Linn.) or are aquatic (including amphibious) in Such conditions are more pronounced in the nature. Common ones among these in the area are Shivalik hills. Tropical type of climate 164 JOURNAL, BOMBAYNATURALHIST.SOCIETY, Vol. 92 (1995) accommodates a very high percentage (35.38%) of the warm and high seasonal rainfall oftropical areas species and includes the elements of tropical, which characterize most countries in south-east Asia subtropical and warm countries. Similarly dry and (eastern element) to the semi-arid Middle-Eastern hot conditions favour the African element extending countries with colder winter and absence of any into the Indian desert in particular or sometimes monsoon influence or marked rainy season. going beyond it. This can be appreciated by the fact It may be concluded that as the area became that the percentage ofthis flora is as high as 13.90% denuded, the original species had to compete with in semi-arid Punjab out of 17.78% of the total the introduced ones. The exotic species; due to their African flora of Punjab State. The fairly good aggressive nature, suitable climate and probably representation of temperate and Mediterranean- disease free environment in their new homes, have Oriental-European elements (10. 19%) is because of been able to colonise the exposed areas and often the cold winter period which permits its penetration displace the previously established species of Indian into the area. The typical New World element is subcontinent. In this connection, a relatively recent extremely poor and constitutes only 4.73% of the case of Parthenium hysterophorus Linn, needs to be total flora. The majority of these American species quoted. This New World species was recorded from like Alternanthera tenella Colla, A.paronychioides Punjabjust over a decade ago (Sharma 1979). During St.-Hil., Argemone mexicana Linn., A.ochroleuca this short period it has assumed the dimensions of an Sweet, Croton bonplandianum Baill., Eichhornia obnoxious and gregarious weed. It has colonized crassipes Solms, Erigeron bonariensis Linn., various areas throughout the State replacing the Gnaphalium pensylvanicum Willd., Gomphrena already thrivingplantspecies from wasteplaces along celosioidesMart.,Hyptis suaveolensPoit.,Ipomoea roadsides and railway tracks. Thus the introduction camea Jacq. subsp. fistulosa D. Austin, Opuntia of the alien plants had a harmful influence on the dillenii Haw., O. stricta Haw., Oxalis corymbosa native vegetation. Consequently, as the settlement DC., O. dehradunensis Raizada, Parthenium advanced the flora began to assume a mixed hysterophorus Linn., Physalis angulata Linn., character. Portulaca pilosa Linn., Prosopis chilensis DC. and Acknowledgements Verbesina encelioides A. Gray have established themselves very well probably because ofthe similar Grateful thanks are due to the Heads ofBotany climatic conditions prevailing in their native areas department of Punjab University, Chandigarh, and new homes. The Western element (26.27%) Punjab Agricultural University, Ludhiana and slightly exceeds the Eastern element (23.51%) in Punjabi University, Patiala for providing assistance the flora of Punjab State. This shows that the area of various sorts. The senior author is also obliged is a meeting place of the Eastern and Western to the authorities of some Indian herbaria (BSD, elements. DD, LWG, CAL) forherbarium and library facilities From theperspective of Punjab flora, the State and to Director, Kew Herbarium, Surrey for the must be categorized largely as a transition zone from identification of some specimens. References Agharkar, S.P. & A.K. Ghose (1931): The composition of the Burma. J. Asiat. Soc.. Bengal II. 5: 19-67. Bengal flora(Abstract).Proc. 18th Indian Sci. Congr. 3(v): Chatterjee, D.(1947): InfluenceofEastMediterraneanRegionflora 278. on thatofIndia.Sci. & Cult. 13: 9-11. Bharucha,F.R.&V.M.Meher-Homji(1965):Onthefloralelements Gaussen, H.(1933):GeographiedesPlantes.CollectACollin,Paris. of the semi-arid zones of India and their ecological & Legris, P. V.M. Mehf.r-Homii (1968): Floral elements in the significance.NewPhytol. 64: 330-342. vegetationofIndia.Proc. Symp. RecentAdv. Trop. Ecol.,pp. Chatterjee, D. (1939): Studies on theendemic floraofIndiaand 536-543. InternationalSocietyforTropicalEcology,Varanasi. — FLORA OFPUNJABSTATE A PHYTOGEOGRAPHICASSESSMENT 165 Maheshwari, J.K. (1962): Studies on the naturalized flora of Sharma, M.(1979): SomeplantsnewtothefloraofPunjabplains. India.In\ Maheshwari, Johri, & I.K. Vasil, (Eds.) J. Bombay nat. Hist. Soc. 74 (Supply. 683-687. Proc. Slimmer Sch. Bot. - Darjeeling, pp. 156-170. Sharma, M. (1990): Punjab Plants, Check-List. Bishen Singh Ministry ofScientific Research and Cultural affairs. New Mahendra Pal Singh, DehraDun. Delhi. Sharma, M., D.S. Dhaliwai., R. Gaba &P. Sharma (1987):Flora Maheshwari,J.K. (1979): Alien floraofIndia.In: Khoshoo, T.N. ofsemi-arid Punjab. Dev Publishers, Patiala. & RK.K. Nair, (Eds.)Progr. PI. Res., pp. 219-228. National Singh, V. (1978): Phytogeographicalreassessmentonthefloraof Botanical Research Institute,Lucknow. Rajasthan. J. Bombay nat. Hist. Soc. 74 (3): 444-452.