96 C. J. HUMPHRIES 



Within the Anthemideae the commonest ligule colour is white or creamy white. The same is 

 true for Anacyclus, where white ligules are found in A. clavatus, A. latealatus, A. linear ilobus and 

 A. nigellifolius. White ligules are also found in A. pyrethrum, A. radiatus subsp. coronatus and 

 A. maroccanus, but the lamina of the ray florets is characterized by having a deep purple stripe on 

 the underside. This feature is always present in A. pyrethrum and A. maroccanus but is frequently 

 absent from plants of A. radiatus subsp. coronatus. The only distinctly radiate species to have 

 yellow ligules is A. radiatus subsp. radiatus and this, like its sister taxon, is known from several 

 sporadic collections to have purple-striped variants frequently referred to var. purpurascens DC. 

 The red-purple stripe is a feature common to a number of widely different Compositae, having 

 been reported from Relhania in the Inuleae (Bremer, 1976), the Arctotideae, the Cichorioideae 

 (e.g. Crepis) and the Anthemideae. There seems to be little or no information about its function; 

 since it is only visible from above during the bud stage of flowering, Bremer (1976) has suggested 

 that it might be a signal block for pollinators in the pre-maturation phase of anthesis. 



The disc-florets are invariably yellow, infundibuliform and divided into a lower tube and an 

 upper 5-lobed bell, which contains the anther tube. In all species, the distinction between the bell 

 and the tube is very clear. The corolla lobes are normally regular cucullate triangular appendages, 

 with a papillate surface on the inner face in most taxa; but in some species, e.g. the annuals 

 A. radiatus, A. clavatus, A. homogamos and A. x valentinus, two of the five lobes can be distinctly 

 longer than the other three. This feature is usually heteromorphic within a capitulum with the 

 most zygomorphic, radiant radiate corollas towards the centre of the head and the most actino- 

 morphic florets towards the periphery. The radiant form seems to be derived by excessive pro- 

 liferation at the dorsal points of the two hooded lobes and is particularly conspicuous in A. 

 clavatus (Fig. 19). 



The corolla tubes of both ray and disc florets are compressed in the anterior-dorsal plane. The 

 net result is that the centre part of the tube is somewhat oval in transverse section and is invested 

 on either margin with a wing of varying dimensions, ranging in width from about 0-5 mm in 

 A. maroccanus to 3 mm in A. nigellifolius. In most taxa the wings have more or less parallel sides 

 and the base of the corolla tube articulates regularly with the ovary. In A. linearilobus (Fig. 24) 

 the wings are somewhat rounded and the dorsal margin extends below the top of the ovary. This 

 phenomenon is even more pronounced in A. nigellifolius (Fig. 26) and in Leucocyclus formosus, 

 where the corolla tube forms an invaginated base shrouding the flattened cypsela on both the 

 anterior and dorsal sides. 



The styles and stamens of both the ray and the disc florets are monotonously constant through- 

 out the genus. The anthers have very short tails consisting of slightly elongated, triangular cuneate 

 apices. The style branches do vary somewhat in length but are invariably truncate-penicillate at 

 the apex. Measurements are given with the descriptions. 



Cypselas 



Despite the pleas of Wagenitz (1976) and Roth (1977) to use the term achene (of Richard, 1808 

 and de Candolle, 1813) to describe the fruit derived from inferior ovaries, the term cypsela of 

 Mirbel (1815) is used in preference to describe the bicarpellate coenocarpous inferior ovary of the 

 Compositae (after Fahn, 1967), since it is clearly not homologous with other monospermous fruits 

 to which the former term was originally applied by Necker (1790). 



In Anacyclus the cypselas are essentially homomorphic although there is some tendency 

 towards heteromorphy, simply because there is a gradual reduction in overall structure from the 

 most elaborate fruits of the ray florets to the smaller cypselas of the central disc florets (Fig. 4). 

 The cypselas in Anacyclus, as in so many other genera of the Anthemideae (Heywood & 

 Humphries, 1977), provide the unambiguous diagnostic features of the genus. They are flattened 

 in an anterior-dorsal plane with distinct lateral appendages. Anatomical features which appear 

 to be confined to this genus and Leucocyclus include a pericarp consisting of a layer of scleren- 

 chyma some 1-3 cells thick, sclerenchymatous ribs, and two laterally orientated vascular bundles 

 (Fig. 5). 



There is considerable variation in the general elaboration of wing shape and in the thickness, 

 size and dimensions of the cypselas and, to a lesser extent, the pappus. Since it seems clear that 



