A revision of the genus Pteronia (Compositae) . 279 



I. Scepinia. — Heads many- or few-flowered. Receptacle alveolate, 

 shortly firabrilliferous. Achenes terete or subcompressed, 

 villous, narrowed slightly into a neck. Leaves alternate or 

 opposite. — 27 species. 

 II. Pachyderis. — Heads many-flowered. Receptacle alveolate. 

 Achenes compressed (outer sometimes trigonous), shortly 

 beaked at the apex, conspicuously attenuated into a thick 

 glabrous neck below the pappus. Leaves opposite, rarely 

 alternate. — 25 species. 

 III. Pterophorus. — Heads many-flowered. Receptacle fimbrilli- 

 fei-ous. Achenes erostrate, flat or compressed. Pappus sub- 

 1 -seriate, setae joined at the base into a ring. Leaves sparse, 

 linear, entire. Heads solitary, terminal ; branches leafy 

 almost to the apex. — 3 species. 

 Eight species are unclassified as being imperfectly known, although 

 nearly all were collected and described by Thunberg. 



De Candolle's arrangement was closely followed by Harvey in 

 Harvey & Sonder, Fl. Capensis vol. iii, published in 1864, so the work 

 of these two authors may be considered jointly. Harvey reduced the 

 number of species to 52, placed the " imperfectly known " ones into 

 the above sections according to their characters, and added an 

 "artificial key to the species." 



It will be observed that there is scarcely any clear dividing line 

 between De Candolle's first two sections, the presence or absence of a 

 distinct neck to the achene furnishing the most definite character. 

 Section Pterophorus, containing only three species (reduced by Harvey 

 to one), is distinguished by the absence of the beak and in a supposed 

 difference in the pappus, a character which appears to us to be of 

 trifling value. We therefore propose an entirely different classifica- 

 tion, based principally on the nature of the indumentum of the leaves 

 or its absence, as affording an easily ascertainable and highly constant 

 character. On this feature alone they may be grouped into four 

 sections as follows : 



I. Incanae. — Nine species, in which the leaves are clothed by a 

 woolly whitish indumentum. 

 II. Papillatae. — Eight species with the leaves densely papillous 

 or scabrid all over the surfaces. 



III. Ciliatae. — Sixteen species with conspicuously ciliate but 



mostly otherwise glabrous leaves. 



IV. GrLABRATAE. — T\venty-eight species, in which the leaves are 



entirely glabrous and fleshy. 

 The Incanae are further characterised by the constantly opposite 



