BS 54 137 Additions to the Yemen Flora Mats Thulin, Abdulnasser Al-Gifri, Mohammed Abdullah Hussein & Saeed Gabali Tiiulin, M., Abdulnasser Al-Gifri, Mohammed Abdullah Hussein & Saf.f.d Gabali. 2001. Addi­ tions to the Yemen Flora. Biol. Skr. 54: 137-153. ISSN 0366-3612. ISBN 87-7876-246-4. Fifty species of flowering plants new to the mainland of Yemen are reported from field trips undertaken in 1992, 1995 and 1998. The species roughly fall into three ecological groups, (1) species from the coastal zone of Hadramaut and Mahrah regions, (2) species from the escarp­ ment mountains and plateau in Hadramaut and adjacent areas, and (3) species from the mon­ soon woodlands of eastern Mahrah close to the Oman border. The species in group (1) were pre­ viously mostly believed to be endemics either of Oman or Somalia. Most of the species in group (2) are previously known from Oman and/or Somalia, and sometimes also from eastern Ethiopia and beyond. The largest group is group (3), with species from the “Dhofar fog oasis”, file fog moisture here supports a woodland that is denser than anywhere else in Yemen. This vegetation is well known in the Dhofar region in Oman, but in Yemen it has remained practically unknown up to now. Many of the species in this group have previously been regarded as endemics of the Dhofar region of Oman, but some of them have more or less wide distributions in tropical Asia or in north-eastern tropical Africa. Mais Thulin, Department of Systematic Botany, Evolutionary Biology Centre, Uppsala University, Norbyvä- gen 18D, SE-752 36 Uppsala, Sweden. E-mail: [email protected] Abdulnasser Al-Gifri, Zayed Complex for Herbal Medicine, P.O. Box 29300, Alm Dhabi, United Arab Emir­ ates Mohammed Abdullah Hussein, Biology Department, College of Education (University of Aden), Zingibar, Yemen Saeed. Gabali, University of Aden, P.O. Box 11038, Khormaksar, Aden, Yemen. Introduction southern Yemen. The second trip took place in Three major botanical field trips to the main­ November 1995, and concentrated mainly on land of Yemen have been undertaken during the Ibb and Taizz regions in northern Yemen. the 1990’s in collaboration between the The third trip took place in November 1998, Department of Systematic Botany at Uppsala and concentrated mainly on the Mahrah University, Sweden, and the Department of region in southern Yemen. Various results Biology, University of Aden, Yemen. The first from these field trips have so far been reported trip took place in October 1992, and concen­ in the following papers: Thulin & Al-Gifri trated mainly on the Hadramaut region in ( 1994), Thulin (1994a, 1994b), Hjertson (1995), 138 BS 54 Thiilin (1995a, 1995b), Thulin & Al-Gifri The species in group (1) include Basananthe (1995), Thulin & Iljertson (1995), Petrusson berberoides, Cleome albescens (subsp. omanensis), & Thulin (1996a), Thulin (1998), Thulin Cocculus balfourii, Commiphora foliacea, C. play- (1999a) and Lönn (1999). fairii, Conocarpus lancifolius, Gymnocarpos rotun- These papers mainly concern new species difolius, Indigofera nephrocarpa, Microcharis dis- described from Yemen and other taxonomic juncta (var. fallax), Schweinfur thia spinosa, novelties, but in Thulin (1995b) Indigofera ere- Suaeda moschata, and Zygophyllum smithii. These mophila Thulin was reported from Yemen for all grow in the stony semi-desert plains, hill­ the first time on the basis of material collected sides or wadis at more or less low altitudes in 1992, and Miller (1996a) reported Commicar- along the coast of Hadramaut and/or Mahrah pus reniformis Chiov. from Yemen for the first (Fig. 1 above), and most of them were previ­ time, also on the basis of material collected on ously believed to be endemics either of Oman our trip in 1992. or Somalia. Only Microcharis disjuncta has a In this paper 50 further species new to the wider distribution in Africa. mainland of Yemen are reported from these The species in group (2) include Azima tetra­ trips. The new records have all been made in cantha, Bauhinia ellenbeckii, Ceratonia oreothauma, southern Yemen, within the Arabian part of Cordia nevillii, Crotalaria dumosa, Cyclocheilon so­ the Somalia-Masai regional centre of malense, Indigofera sedgewickiana, Indigofera endemism (White & Léonard 1991), and in volkensii, Nannorrhops ritchieana, Pappea capensis, areas not covered by the recent A handbook of and Sporobolus ruspolianus. Most of these species the Yemen Flora (Wood 1997). The area is cov­ are found in Yemen either on the steep, period­ ered by Flora of the Arabian Peninsula and Socotra ically mist-covered escarpments above the of which the first volume has been published coastal plain in Hadramaut, or on the plateau (Miller & Cope 1996). Another basic works for itself. Indigofera sedgewickiana is an exception, as the area is Flora des tropischen Arabien by it is so far only known from the mountains of Schwartz (1939). The species in the present Lahij rather than from Hadramaut. Phytogeo- account are arranged alphabetically within the graphically it is a rather mixed group, but most families, and the families are arranged alpha­ of the species are previously known from Oman betically as well. and/or Somalia (and eastern Ethiopia and bey­ The species may also be arranged ecologic­ ond). Only Pappea capensis and Azima tetracantha ally into the following three groups: are widespread species in Africa, with Azima (1) species from the coastal zone mainly of the tetracantha extending also to tropical Asia. Hadramaut and Mahrah regions, The largest group is group (3), which (2) species from the escarpment mountains includes Anogeissus dhofarica, Blepharis dhofaren- and plateau (Joi) in Hadramaut and adja­ sis, Blepharispermum hirtum, Corallocarpus epi- cent areas, and gaeus, Commicarpus boissieri, Croton confertus, (3) species from the monsoon woodlands of Cucumis sativus, Dhofaria macleishii, Diplocyclos eastern Mahrah along the escarpments palmatus, Dyerophytum indicum, Euphorbia close to the Oman border. smithii, Gossypium stocksii, Impatiens balsamina, Fig. 1. Above: view of Wadi Art in the foothills near the coast of Hadramaut, with trees of Conocarpus lancifolius visible as dark dots along the wadi. Photo by M. Thulin, 5.X.1992. Below: view of the escarpment woodland in eastern Mahrah, near Sadfan, with branches of Euphorbia smithii in the foreground. Photo by M. Thulin, 11.X.1998. BS 54 139 140 BS 54 Jatropha dhofarica, Justicier diffusa, Lavandula though, that this unique vegetation is better dhofarensis, Leucas dhofarensis, Ocimum dho- preserved in Yemen than in Oman, where it is farense, Ormocarpum dhofarense, Pulicaria oma- said to be under serious threat (Miller 1994). nensis, Remusatia vivipara, Rungia pectinata, During our trip in 1998 we also discovered Ruttya fruticosa, Sida cordata, Trichodesma hilde- some very isolated patches of a depauperate brandtii, Vatovaea pseudolablab, and Withania kind of monsoon woodland al about 800-850 in qaraitica. These species are all found on the altitude near the top of Ras Fartak some 150 fog-affected escarpment mountains of south­ km from the Oman border. These woodland ern Arabia called the “Dhofar fog oasis” (Miller fragments contained fewer woody species than 1994), which arc covered by dense woodlands those close to the Oman border, and mainly on the seaward-facing slopes (Fig. 1). The area Acokanthera schimperi (not seen closer to is in the monsoon belt and from about mid­ Oman), Anogeissus dhofarica, Euclea schimperi, June to mid-September each year the area Croton confertus, and Olea europaea subsp. cuspi- comes under the influence of the south-west data, were noted. monsoon that causes dense fog to build up All the species listed above in this group are against the seaward-facing escarpments. The previously known from Oman, and many of high quantities of drip-precipitation from fog them have been regarded as endemics of the moisture, in addition to the rainfall (Miller Dhofar region of Oman. However, some of 1994), support woodland that is denser than them, such as Cucumis sativus, Dyerophytum anywhere else in Yemen. This vegetation is well indicum, Impatiens balsamina, Remusatia vivip­ known in the Dhofar region in Oman, and ara, Rungia pectinata and Sida cordala, also have many of the plants found there are described wider distributions in tropical Asia, and and illustrated in the book by Miller & Morris Remusatia vivipara is relatively widespread also ( 1988). In Yemen, where this vegetation covers in tropical Africa. Ruttya fruticosa, Trichodesma a narrow band for about 30 km along the coast hildebrandtii and Vatovaea pseudolablab all have west of the Oman border, it has remained prac­ more or less wide distributions in north-east­ tically unknown because of the remoteness and ern tropical Africa. inaccessibility of the area. Our results show that all the dominant woody plants of these woodlands in Oman, Acanthaceae such as Anogeissus dhofarica, Blepharispermum hir- Blephciris dhofarensis A.G. Miller tum, Croton confertus, Euphorbia smithii and Jat­ Yemen. Mahrah: Sadfan, along road between ropha dhofarica, are present and have the same Jadib and Damqawt, then inland along track, role also in Yemen. Of these, all, except Croton 16°38’N, 52°56’E, 11.XI.1998, Thulin, Beier & confertus, which is known from Somalia, were Mohammed Hussein 9715 (K, UPS); escarpment previously believed to be endemics of Oman. NE of Hawf, 16°39’N, 53°03’E, 13.XI.1998, Many other plants of these woodlands that Thulin, Beier & Mohammed Hussein 9778 (K, were previously believed to be endemics of UPS); near Yemen/Oman border crossing NE Oman are also present on the Yemen side, and of Häuf, 16°40’N, 53°05’E, 12.XI. 1998, Thulin, surely there arc still more to be found. Beier & Mohammed Hussein 9748 (UPS). The monsoon woodlands in Yemen are still Blepharis dhofarensis is known previously only largely intact, although Hatter areas have often from the Dhofar region in Oman (Miller in been opened up for the cultivation of Miller & Biagi 1988; Miller & Morris 1988), sorghum, etc.