1953] 



VEGETATION OF NYAS ALAND 



181 



Among conspicuous late flowering tall herbs, largely Compositae, were Laggera 

 alata (D. Don) Sch. Bip., Schistostephium art emisii folium Bak., Helicbrysum 

 kirkii Oliv. & Hiern, Polygala gomesiana Welw., and Acrocepbalus callianthus 

 Briq. On a field estimate, about one-third of the herbs were of species that also 

 occurred on the lower plateau of Zomba Mountain on the eastern side of the Rift. 



When we began our first stay at Nchisi, late in July, the annual burning 

 of the grass had already begun, and distant views were obscured by haze after 

 early morning. The grassfires were chiefly at lower elevations, down in the 

 Rift, but patches had been burned in drier parts of the woodlands at Nchisi. 

 We had been told that no rain fell in this area between April and mid-December. 

 On July 29, however, chiperoni conditions prevailed, with mist down to the 

 ground most of the day, and some light rain. Again, on September 12, a smart 

 fall of rain yielded perhaps half an inch. Such off-season rains and mists per- 

 haps made possible the development of the tall rain forest on the mountain. 



As the dry season advanced and spring gave way to climatic summer, it 

 became evident that the growth and reproduction cycle of many plants of the 

 woodlands was influenced more by such factors as temperature and length of day 

 than by rain and available ground moisture. This was especially evident in the 

 deciduous Brachystegia and Isoberlinia trees, which broke out into new leaf 

 during the first week of September, and with the bright reds and coppery browns 

 of their young foliage transformed the countryside. Flower buds appeared with 

 the new leafage but did not open before we finally left the area on September 

 13. The leafing out of the Brachystegia trees is considered to mark the beginning 

 of summer in these latitudes in East Africa. 



Grass-fires had important effects upon the woodland vegetation apart from 

 actual burning. They hastened leaf-fall in the deciduous trees and this resulted 

 in an earlier showing of young leaves. Soon after the grasses had been burned 

 they sent up young shoots from amongst the blackened stubble. With the young 

 grass growths appeared the showy flowers of numerous perennial herbs, while 

 on adjoining ground that escaped the fire there was not a sign of new growth. 

 Common herbs or subshrubs thus flowering in the neighborhood of Nchisi in 

 early September, 4 to 6 weeks after fires, included Gnidia buchanani Gilg, 

 Lasiosipbon kraussianus (Meisn.) Burtt Davy, Crepis newii Oliv. & Hiern, 

 Berkbeya insignis (Harv.) Thell., Caucalis pedunculata Bak. f., Osteospermum 

 mono cepb alum (Oliv. & Hiern) Norlindh., Lotononis laxa Eckl. & Zeyh. var. 

 multi flora D'lmmer, and Rhynchosia insignis (O. Hoffm.) R. E. Fries. Some 

 of these species, though in full flower, had not yet produced leafy shoots from 

 their deep taproots or woody or fleshy rootstocks. 



The plant collections of the expedition from Nchisi and vicinity totalled 306 

 numbers. 



Nyika Plateau. Rising from the western edge of the Rift, steep- sided on all 

 fronts, the Nyika Plateau is about 40 miles across in its widest part and approxi- 

 mately 900 square miles in area. For the most part it is a great upland of smooth 

 grassy ridges with an average elevation of 7,000 to 7,500 feet. Eminences attain 

 often 8,000 feet, and on the eastern rim as much as 8,400 feet. The Nyika up- 

 lands are the most lofty in Nyasaland. On them a small population, known as 

 the Apoka, lives at altitudes higher than any other people in the country. Well 

 armed with bows and spears, the shy Apoka descend from the plateau with big 

 balls of cured tobacco and gourds of honey for trade. If cattle or other domestic 

 animals were grazed on the plateau, I saw no signs of them. Zebra and eland were 

 fairly plentiful. 



