Page 169 A CHECK LIST OF PLANTS RECORDED IN TSAVO NATIONAL PARK, EAST By P. J. GREENWAY INTRODUCTION A preliminary list of the vascular plants of the Tsavo National Park, Kenya, was prepared by Mr. J. B. Gillett and Dr. D. Wood of the East African Herbarium during 1966. This I found most useful during a two month vegetation survey of Tsavo, East, which I was asked to undertake by the Director of Kenya National Parks, Mr. P. M. Olindo, during "the short rains", December-January 1966-1967. Mr. Gillett's list covered both the East and West Tsavo National Parks which are considered by the Trustees of the Kenya National Parks as quite separate entities, each with its own Warden in Charge, their separate staffs and organisations. As a result of my two months' field work I decided to prepare a Check List of the plants of the Tsavo National Park, East, based on the botanical material collected during the survey and a thorough search through the East African Herbarium for specimens which had been collected previously in Tsavo East or the immediate adjacent areas. This search was started in May, carried out intermittently on account of other work, and was completed in September 1967. BOTANICAL COLLECTORS The first traveller to have collected in the area of what is now the Tsavo National Park, East, was J. M. Hildebrandt who in January 1877 began his journey from Mombasa towards Mount Kenya. He explored Ndara and the Ndei hills in the Taita district, and reached Kitui in the Ukamba district, where he spent three months, returning to Mombasa and Zanzibar in August. Next the famous geologist and explorer J. W. Gregory collected in our area during January to March 1893 reaching Mtito Andei on the 23rd March on his jour• ney to the Rift Valley. Then in November 1893, G. F. Scott Elliott began his journey from Mombasa to Ruwenzori collecting plants on his way. Another collector, T. Kassner, passed through our area on his way from Mombasa to Nairobi in the first half of 1902 and again in 1909. The next collector seems to have been a member of the Agricultural Department, J. MacDonald who obtained a few plants near Voi in 1924. Then between April and June 1931 Miss E. R. Napier, one time botanist of the Coryndon Museum, worked around Voi, and along the roads Voi to Taveta and Voi to Tsavo. It was she who first found a Moringa which is new to science and has still to be described and named. Another lady, Miss J. Ossent, working for a firm of contractors making the pipes for the Mzima Springs-Mombasa pipe line, was stationed at Voi in 1955 and 1956 and by her collections of plants around Voi and along the Mombasa-Nairobi Road between Voi and Mtito Andei increased our knowledge of the flora of Tsavo East. From that period until the present, a whole series of collectors, mostly passing through have collected sporadically between Mtito Andei and Mackinnon Road along the Nairobi-Mombasa Road. Among the many, have been C. G. Macarthur of the Game Department, P.R.O. Bally, botanist of the Coryndon Museum, A. Bogdan, Pasture Research Officer, Agricultural Department, B. Verdcourt of the E. A. Her• barium, Drummond and Hemsley of the Royal Botanic Gardens, Kew, R. Polhill of Kew with Samuel Paulo Kibuwa of the E. A. Herbarium and myself and others in passing when)hey saw a plant in flower which attracted their attention. Page 170 Of residents in Tsavo National Park, East, the Chief Warden, D. L. W. Sheldrick and others such as P. Napier Bax, C. Moore and R. Schenkel have been particularly active in collecting plants that are eaten by elephants, rhino and other game animals. Recently Mr. and Mrs. P. Hucks, by collecting and photograping the plants in Tsavo East have contributed greatly to our knowledge of the flora. They camped at Voi within the Park and travelled almost daily over several months in search of plants in flower, to photograph in colour, pressing and drying the plant photographed so that the photo is supported by a voucher specimen. To date they have collected over 1,100 specimens and a duplicate of most are deposited in the E. A. Herbarium as well as at the Voi Headquarters of the Tsavo National Park, East. During my stay at Voi in December and January with the the help of my field assist• ant, Mr. Kanuri Kabuie, we collected over 450 numbers of plants in sets of five which have been named and a set of each deposited in the E. A. Herbarium, Nairobi, the Voi Headquarters of Tsavo East, the Royal Botanic Gardens, Kew and elsewhere. This collection has added considerably to the Cyperaceae and Gramineae as well as to other genera recorded in Tsavo East. The collection of botanical material continues by Dr. A. D. Q. Agnew and others with the aid of students of the University College, Nairobi, and the results of their finds are quoted from time to time in the Check List and I acknowledge with grateful thanks the help and comments of Dr. Agnew who has read through the List. In spite of all this collecting activity a great deal more is necessary before we can say that the flora of Tsavo East is well known. Most of the collecting has been done along the roads and tracks between the Galana River and the Park boundary of the Nairobi-Mombasa Road. More is necessary in the north-west from Manyani-Lugard's Falls Road up to Mtito Andei. Again the area in the south-east, Ndara-Dika Plains• Aruba Lodge-Buchuma Gate-Mackinnon Road, the south of the Aruba Lodge-Sala Gate Road and the Eastern boundary from Mackinnon Road down to the Sala Gate has hardly been touched. Thence northwards from the right bank of the Galana and the Athi rivers to the north-east, north and north-west boundaries including the Yatta Plateau is for all practical purposes botanically almost unknown. Myself, I have not been in this area of the Park because during my December-January visit these areas were so dry that the rangers in the Northern Area Headquarters had to be withdrawn as the water supplies had dried up. THE VEGETATION .If one examines the Ordanance Survey I :250,000 maps covering Tsavo National Park, East, the vegetation is indicated by the wording "Bush" or "Thicket" to which the words "Dense", "Medium", "Light" or "Scattered" are prefixed, sometimes "Bush and Scattered Trees", but there are no indications of Grassland. In places there are blue lines or broken-line stipples, particularly in drainage lines and river courses, the solid lines indicating "Marsh" and the broken ones "Marsh, seasonal". Most of these "Marsh" areas lie in the northern portion of the Park, an area I have not seen. They may be Flood Plains Grassland or even Riverine Forest as between the Park Air Strip and the I,600ft. contour line along the Voi River. The main vegetation types met within the area southwards of the Athi-Galana Rivers to the southern side of the Park bounded by the Nairobi-Mombasa Road from Manyani Gate to Voi thence the Voi Gate-Ndara Circuit by way of Aruba Lodge down to the Sala Gate in the east are as follows: I Forest. (a) Ground-water Forest: Fringing or riverine forest: Swamp Forest Palm Stands. Page 171 2 Woodland. 3 Wooded Grassland. (a) Grouped-tree grassland. (b) Scattered-tree grassland. (c) Shrub or Dwarf tree grassland. 4 Grassland. The Galana River Grass Fringe. 5 Swamp Vegetation. 6 Bushland. (a) Ever-green Bushland. (b) Thicket. Ever-green thicket. 7 Vegetation of Rocky Hills and Rock Pavements. 1 Forest. (a) Ground-water Forest. The greater part of this is Riverine Forest with a very limited amount of Swamp Forest. In Tsavo East the riverine forest consists of a continuous stand of trees which attain a height of 60ft. (c.18m.) with crowns touching or intermingling, sometimes freely interlaced with lianes. The canopy is not very dense nor does it consist of several distinct layers. Epiphytes such as orchids and ferns are not evident. The trees have simple or buttressed boles and some of them are in full leaf all the year round. The forest floor is covered with herbs and shrubs where the light penetrates. The Riverine Forest and Swamp Forest can be observed along the banks of the Voi and Galana Rivers. That along the Voi River consists of small stands of Fresh-water Swamp Forest near the Voi-Mombasa Road which thins out soon after passing Ndo• 1010 and then becomes a very thin and broken strip on both banks of the river of Fringing Forest. Its chief components are: Trees: Frequent, Dobera glabra, Newtonia hildebrandtii var. hildebrandtii. Common, Acacia sp., Kigelia africana. Occasional, Albizia glaberrima var. glabrescens, A. zimmermannii, Ficus ingens, F. sycomorus, Tamarindus indica and Terminalia kilimandscharica. Shrubs: Frequent, Azima tetracantha, Capparis sepiaria var. fischeri, Pluchea dioscoridis, P. ovalis, Salvadora persica, and Combretum ukambensis, locally frequent. Common, Cordia goetzei, Gardenia jovis-tonantis, Lawsonia inermis, Vernonia hildebrandtii, with Lecaniodiscus fraxinifolius and Meyna tetraphylla locally common, and Ziziphus mucronata, rare. On the Galana River the fringing forest is of quite a different composition, the fringe of trees thinner and confined strictly to the immediate banks of the river, al• though it is said to have been denser until the great floods of 1961. Here in the riverine forest you have two sub-types, Palm Stands of Hyphaena coria• cea, consisting of a thin line of branched palms up to 50ft.