TAXONOMIC STUDY OF THE GENUS ZIZIPHUS MILL . ( RHAMNACEAE ) OF BANGLADESH

A taxonomic account of six species of Ziziphus Mill., viz. Z. funiculosa Buch.-Ham. ex Lowson, Z. glabrata Heyne ex Roth, Z. mauritiana Lam., Z. oenoplia (L.) Mill., Z. rugosa Lam., and Z. xylopyrus (Retz.) Willd. occurring in the flora of Bangladesh has been given. A dichotomous key to the species has been furnished. An updated nomenclature including important synonyms, selected references, description of the taxa along with illustrations, ecological notes, specimens examined and geographical distribution have been provided. Bangla and English names, flowering and fruiting periods, chromosome number and economic importance have also been presented where available. Introduction The genus Ziziphus Mill., belonging to the family Rhamnaceae, is characterized for its 3 or 5-nerved leaves and drupaceous fruits with a solitary pyrene. It consists of about 135 species, distributed in the temperate and tropical parts of the world, mostly concentrated in Asia and America; although a few of them extend in the Pacific Islands and Australia (Bhandari and Bhansali 2000). There are 17 species in India (Bhandari and Bhansali 2000) and six species in Pakistan (Qaiser and Nazimuddin 1981). Long and Rae (1991) listed seven species in Bhutan, while Hara and Williams (1979) recorded eight species in Nepal. There has been no systematic study of the genus Ziziphus in Bangladesh. Prain (1903) recorded five species and one variety for the greater Bengal of which only four fall in the territory of Bangladesh. Hooker (1875) included 18 species from the whole of British India out of which five were mentioned from the area of present Bangladesh. Uddin et al. (2000) added one species to the account of Ziziphus, viz. Z. xylopyrus for Bangladesh. A literature survey of relevant floristic works, viz. Roxburgh (1832), Hook. f. (1875), Prain (1903), Brandis (1906), Heinig (1925), Cowan (1928), Cowan and Cowan (1929), Kanjilal et al. (1934), Raizada (1941), Datta and Mitra (1953), Sinclair (1955), Khan and Afza (1968), Khan and Banu (1972), Huq and Khan (1984), Khan et al. (1984), Alam (1988), Khan et al. (1994), Mia and Khan (1995), Rahman and Hassan (1995), Rahman and Uddin (1997), Uddin et al. (1998), Uddin and Rahman (1999), Corresponding author. E-mail: bnh_mirpur@yahoo.com Department of Botany, University of Dhaka, Dhaka 1000, Bangladesh.


Introduction
The genus Ziziphus Mill., belonging to the family Rhamnaceae, is characterized for its 3 or 5-nerved leaves and drupaceous fruits with a solitary pyrene.It consists of about 135 species, distributed in the temperate and tropical parts of the world, mostly concentrated in Asia and America; although a few of them extend in the Pacific Islands and Australia (Bhandari and Bhansali 2000).There are 17 species in India (Bhandari and Bhansali 2000) and six species in Pakistan (Qaiser and Nazimuddin 1981).Long and Rae (1991) listed seven species in Bhutan, while Hara and Williams (1979) recorded eight species in Nepal.
The present paper deals with the detailed account of all the six Ziziphus species of Bangladesh.The illustrated taxonomic descriptions with bracketed key to the species, updated nomenclature along with important synonyms, notes on ecology, geographical distribution on global context and within Bangladesh are presented under each taxon.Flowering (Fl.) and fruiting (Fr.) time of the species have been cited while chromosome numbers, Bangla and English names have been provided where available.All the specimens examined have been cited.The district names given under specimen citation are in an alphabetical order.The enumeration is presented in an alphabetical order of the accepted names of taxa.

Materials and Methods
The present work is mainly based on the herbarium specimens housed at Bangladesh National Herbarium (DACB), Central National Herbarium (CAL), and Dhaka University Herbarium indicated in the text as DUH as well as on the survey of literature, namely Farr et al. (1979), Hara and Williams (1979), Qaiser and Nazimuddin (1981), Bhandari andBhansali (1990, 2000) and Long and Rae (1991).
Economic importance: The wood of the tree is reddish in colour and hard in quality.It is used in agricultural implements.It is also used as fuel and charcoal (Bhandari and Bhansali 1990).Fruit acts as a medicine in astringency, stomatche, biliousness, digestion, blood purification, laxative, scabies, throat troubles, nausea and vomiting.It also possesses emollient and pectoral properties.Bark is also used in astringency and in diarrhoea.Powder of the bark is used in dressing to wounds.The powder is also an effective medicine in ulcers.Root is helpful in curing fever, delirium, purgative, gout and rheumatism.Tender leaves and twigs cures boils, abscesses and carbuncles (Yusuf et al. 1994).
Ecology: Grows in hill slope and top of the hill.