Ass. Univ. Bull. Environ. Res. Vol. 15 No. 2 October 2012 Ass. Univ. Bull. Environ. Res. Vol. 15 No. 2 October 2012 AUCES STUDIES ON THE FLORA OF YEMEN: 2-FLORA OF TOOR AL-BAHA DISTRICT, LAHEJ GOVERNORATE, YEMEN Abdo, M. A. Dahmash*; Othman S. S. Hamood** and Salah, M. I. El-Naggar*** *Biology Department, Faculty of science, Sana, a Uuiversity, Yemen **Biology Department, Faculty of Education, Aden Uuiversity, Yemen ***Botany Department , Faculty of science, Assiut Uuiversity, Egypt ABSTRACT: Toor Al-Baha of Lahej governorate (Yemen) lies between latitudes 12° 58` - 13° 20` N, and longitudes 44° 11` - 44° 39`E, has been studied floristically. This region covers about 1883 sq km. Analysis of the floristic composion of the studied area have been carried out and proved that, about 560 taxa belong to 288 genera and 89 families of the vascular plants have been recorded. Of these, the largest families are: Poaceae, Asteraceae, Asclepiadaceae, Euphorbiaceae, Fabaceae, Acanthaceae, Capparaceae, Lamiaceae, Boraginaceae, Malvaceae, Solanaceae, Mimosaceae, Tiliaceae, Amaranthaceae, Cucurbitaceae, Convolvulaceae and Scrophulariaceae, while the largest genera are: Euphorbia, Acacia, Grewia, Heliotropium, Indigofera, Barleria, Eragrostis, Aloe, Hibiscus, Solanum, Tephrosia, Cadaba, Crenulluma, Ficus, Justicia, and Senna. It was also noted that the generic index = 1.94. Sixty eight succulents taxa belong to eighteen families were recorded in the flora of the studied area, among these families six are the richest ones: Asclepiadaceae, Euphorbiaceae, Aloaceae, Aizoaceae, Crassulaceae and Vitaceae. Twenty eight taxa are endemic to flora of Yemen, among them Rhytidocaulon splendidum T. A. McCoy is endemic to Toor Al-Baha only. Another thirty four taxa are found to be near endemic to the flora of Yemen. INTRODUCTION: the south, Sultanate of Oman in the east, and the Red Sea in the west (Fig. 1). Yemen contains The Republic of Yemen lies in the one of the most diverse floras of the Arabian southwestern corner of the Arabian Peninsula. Peninsula region (Wood, 1997 and Al-Dubai, It extends between latitudes 12° 40` to 19° 00` N. 1998). The flora of this country is characterized and longitudes 42° 30` to 53° 05` E. It is by its high diversity and density, particularly in bordered by Kingdom of Saudi Arabia in the the South and West regions, that makes it a north, the Arabian Sea and the Gulf of Aden in complex one. This flora having affinities with -63- Ass. Univ. Bull. Environ. Res. Vol. 15 No. 2 October 2012 the floras of the Tropical African, Sudanese Dhalaa governorates and some parts of Taiz region, the Saharo-Arabian region, the governorate, in the south by Aden governorate Mediterranean countries and the Irano- and the Gulf of Aden (Fig. 1). Lahej governorate Turanian region (Zohary, 1973; Al-Hubaishi & consists of 15 districts. Toor Al-Baha district is Muller-Hohenstein, 1984; Takhtajan, 1986; one of them. It extends between latitudes 12° 58` White & Léonard, 1991; Akhan, 2007). - 13° 20` of the North Latitude and 44° 11` - 44° The flora of Yemen is very rich and diverse. 39`of the East Longitude, with an area of about Species diversity is a result of considerable 1883 sq km. It represents about 14.4 % of total climatic changes in former periods, which area of the governorate. The central of this enabled different species to survive in the district distances from Al-Hawtah district (the different ecological habitats. Previous studies capital of Lahej governorate) about 68 km east. reported that, there are about 2810 plant species Toor Al-Baha district is bordered by Al- belong to 1006 genera and 173 families in Qubaytah district in the north, Al-Maqatrah Yemen. Of these about 2559 are naturalized, district, Al-Madaribah and Ras Al-Aarah 121 cultivated and 111 introduced (Al-Khulaidi, district in the west, Tuban district in the east 2000). On the other hand, Yemen is rich in the and by Gulf of Aden and parts of Aden endemic plants, with estimated to be 415 plant governorate in the south (Fig. 1). species (236 in Socotra). The majority of The topography of the study area comprises endemic taxa in Yemen are associated with different habitats. Of these are: mountains, mountainous areas, which provides a rich intermountain basins (Wadis), alluvial plains, variety of ecological niches and offers a degree hills, slopes and sandy dunes, with altitudinal of environmental stability during periods of ranging between 200-1488 m a. s. l. The geology climate changes. Endemism is generally very of study area is characterized by exposures of high among the succulent plants. The largest rock units from the Paleozoic ages (Proterozoic) numbers of endemic species are found within to the Quaternary. The oldest units are of the Asteraceae, Euphorbiaceae, Acanthaceae, basement rocks composed in dominant from Boraginaceae and Apocynaceae taking into metamorphic rocks of schist and gneiss which account the Stapeliad genera (Caralluma, intruded by granite, diorite and grano-diorite Duvalia, Huernia and Rhytidocaulon) (Al- bodies, this type of rocks exposed particularly in Khulaidi, 2000; Ministry of Water and the most northern part of the studied area Environment, 2010). (Strojexport Foreign Trade Corporation, 1988). The study area is a district of Lahej There are a few studies on the flora and governorate, located at the southwestern part of vegetation of Toor Al-Baha, as a distinct area, Yemen. This governorate is bounded in the east were carried out, of these are: White & Sloane by Abyan governorate, in the west by Taiz (1937); Albers & Meve (2002) and McCoy governorate, in the north by Al-Bayda, Al- (2003). Some other scholars studied the flora of -64- Ass. Univ. Bull. Environ. Res. Vol. 15 No. 2 October 2012 Toor Al-Baha among the southern governorates Al-Gifri & Gabali (1991). of Yemen such as: Gabali & Al-Gifri (1990); Fig. 1: Map of Yemen (modified afterhttp://www.worldatlas. com/web image/ country's/ asia/ye.htm), showing political map of Lahej governorate with browsing the location of study area -Toor Al-Baha (modified after Ministry of the Local administration) The present study aims to carry out a selected area, to analysis the floral composition comprehensive survey of the natural flora of the of the studied area and to give an annotated -65- Ass. Univ. Bull. Environ. Res. Vol. 15 No. 2 October 2012 checklist of the flora of the studied area as a alphabetically. Voucher specimens for each step towards understanding the flora of Yemen taxon reported are kept in each of: Herbarium as a whole. of Biology Department, Faculty of Science, Sanaa University, Herbarium of Biology MATERIALS AND METHODS: Departement, Faculty of Education, Aden University (Yemen) and the Herbarium of The field studies were carried out through Assiut Universty, Egypt (ASTU). several trips during the different seasons between 2008 and 2011. About 4-8 (-10), trips RESULTS AND DISCUSSION: per month were conducted. One hundred sites and 280 quadrates were selected to cover all the A total number of the vascular plant which different habitats and floral composition of the has been recorded from the studied area is 560 studied area. For each taxon at least three taxa related to 288 genera and 89 families duplicates of representative plant specimens (Fig. 2). These numbers are very high comparing were collected, with respect to their coordinates with those have been recorded from other (latitude, longitude and altitude using GPS regions or governorates of Yemen, even their systen). climates are humid arid. If we have a look at the The collected specimens (un-diseased, and previous results of the floristic composition in not seriously damaged by insects or other other governorates of Yemen, we can note that, agencies) including flowers and or fruits as well the flora of the studied district is very rich and as leaves and stems (Plants of small or moderate diverse. size, herbs and small shrubs), were dug up Based on the data from the literature, carefully and collected as a whole, including the Gabali and Al Gifri (1990), recorded only 467 underground parts (roots, rhizomes, tubers and taxa from the whole southern governorates of bulbs). Yemen. Also Boulos in 1988 visited the southern The plant specimens were pressed in the governorates (Abyan, Aden, Hadhramout, field and transported to be continued in the Lahej and Shabwah) with other Yemenis laboratory. When the specimens were botanists and they recorded 378 taxa of all these completely dried, each individual specimen was governorates. On the other governorates even mounted on a herbarium sheet. For each taxon the climate is humid arid, wetter, (high rainfall collected at least three dried specimen were and low temperate) as in Ibb, Al-Mahweet, mounted on herbarium sheet and labeled. Hadhramout and Hauf district (Al-Mahrah) the Arrangement of the families in the present number of the collected taxa was less than that work was followed the system proposed by collected from Toor Al-Baha. Aqlan in 2008 Cronquist, 1981, while the genera and species reported that about 416 taxa from Ibb within each family were arranged governorate. Ibrahim (2006) recorded about 385 -66- Ass. Univ. Bull. Environ. Res. Vol. 15 No. 2 October 2012 taxa from Al-Mahweet governorate. While, different genus is relatively more diverse than from Hadhramout governorate, Al Khulaidi that a region with the same number of species (2010) recorded about 469 taxa of the whole but belong to a few number of genera governorate. After different studies on the (Hawksworth, 1995; Khedr et al., 2002). vegetation of Hauf district, Hussein (2006) From the recorded 89 families in the present recorded 236 taxa only. investigation, there are only three families of As we usually state that the flora of Toor Pteridophyta which represent 3.37% of the Al-Baha district is very rich floristically, since it recorded families, while only one family of the comprises about 560 taxa.