Vernonia chloropappa (Compositae) and Related Species in Tropical Africa

Abstract

Vernonia chloropappa Bak. belongs to a group of annual vernonias centred on the area between northern Lake Malawi and southern Lake Tanganyika. Characteristic for this group is the small distinctive achene, 1-5-2-5 mm long, subcylindric, terete or very narrowly c. 5-ribbed and strigulose, with the outer pappus elements reduced to a short fringe of scales. The group is remarkable for the frequent, though irregular, occurrence within its species of green or greenish inner pappus setae and creamy-white to pale-mauve corollas-this in a genus where the pappus elements are more usually white, sordid, brown or purplish and the flowers purple or blue. Baker in describing V. chloropappa gave as the type for the name a Whyte gathering from northern Malawi. Unfortunately this specimen is a mixture of two elements. One element of Baker's type, designated by myself on the Kew sheet as element A and here selected as the lectotype of V. chloropappa, is distinguished by its long lax 'peduncles', silvery-tomentellous involucres, and phyllaries which are not produced into an apical bristle. The other, element B, has shorter 'peduncles', brownish-hispid involucres and attenuate-aristate phyllaries and is described below as V. jelfiae S. Moore var. albida. V. smaragdopappa S. Moore, based on a plant from Zaire, is conspecific with V. chloropappa. V. smaragdopappa is the name proposed by S. Moore for V. kaessneri of De Wildeman & Muschler, the latter being a later homonym of V. kaessneri S. Moore.