216 MR, А. W. HILL ON THE 
The Acaulescent Species of Malvastrum, A. Gray. 
By Автнов W. Нил, M.A., F.L.S. 
[Read 17th June, 1909.] 
THE small group of acaulescent Malvaceæ from the Andes, which form the 
subject of this paper, were referred by Gray to the genus Malvastrum, but 
were considered by Weddell to belong to Malva*. Не retained the name 
Malvastrum for those plants in which the peduncles were adnate to the 
petioles and whose flowers were destitute of an involucre ; these are now 
included in the genus Nototriche f. Weddell’s acaulescent species of Malva 
were described as having flowers with or without an involucre and with the 
peduncles axillary or radical. The species with those characters, following 
Gray and Baker fil., are retained in Malvastrum. Weddell also broke up his 
andine Malvas into two sections, on the character of the presence or absence 
of the involucre; but it will be shown that the two species M. nubigena and 
M. oriastrum of his second section “ Flores involucello destituti " apparently 
possess an involucre which may be caducous or sometimes aborted. 
The acaulescent species of Malvastrum form a small and possibly not very 
natural group, since they probably represent the high alpine forms of this 
large genus and may perhaps be more closely related to some caulescent 
forms—living or extinct—than they are to each other. In their general 
facies they resemble the species of Nototriche and exhibit a similar adaptation 
to conditions, The plants have usually thick tap-roots in continuation of the 
woody underground caudices. In M. Hauthalii the caudex was found to be 
L5 em. in diameter with a length of 18 em. preserved. The caudices 
appear to be unbranched in almost every case, so that the plants possess only 
a single leaf-rosette. The leaves, borne on fairly long petioles, are spread out 
on the ground. They are usually more or less orbicular or ovate in outline, 
either entire, M. alismatifolium, or with a crenate margin, M. betonicæfolium, 
&c., or more or less deeply 5-7-lobed. They may be cordate, truncate, or 
cuneate at the base. The veins are usually palmate, but in some cases they 
are pinnately arranged. As a rule, the leaves are glabrous above, and if hairy 
below, the hairs are often confined to the veins. If the upper surface is hairy 
the lower is much more 50. The tomentum, except in one or two species, is 
unlike that obtaining in Nototriche; the stellate hairs have usually only 2 or 3 
rays or may be reduced to single bristles, and the plant thus appears to be 
* Weddell, Chl. And. ii. p. 273. 
T Hill, A. W., in Engl. Bot. Jahrb. xxxvii. (1906) p. 576. 
