396 Hill. — The Morphology and Seedling Structure of the 
a large number of seedlings in the moss surrounding some of the plants, 
that I was led to investigate all the bulbous and tuberous specimens of 
this genus preserved in our herbaria, in addition to those in my own collec- 
tion. These peculiar geophilous forms, which are often less than an inch 
in height, occur in South America, in the Andes of Peru, Bolivia, and 
Northern Argentina, and in Central America, in the mountains from 
Guatemala to Mexico. 
The South American specimens resemble minute Cyclamen plants in 
their habit of growth to a very close degree. In all the known species the 
underground portion is a corm or tuber, which is more or less spherical, 
but becoming ovoid, or rather irregular in shape, in old plants. There 
appear to be two types of corm or tuber exhibited by the South 
American species. In the one case the roots are borne in a median 
basal tuft on the under side of the corm, in the position of the primary 
root, and to this type belong P. parvi folia , C. DC. (Fig. 27, PI. XXIX), 
P. verruculosa , Dahlst., &c. ; whilst in the other case, of which P. peruviana, 
(Miq.) Dahlst. 1 (Figs. 1 and 2, PL XXIX), A. macrorhiza , and P. umbilicata , 
R. and P. \ & c., appear to be typical, the median primary root is supplanted 
by lateral adventitious roots arising from the sides of the tuber. The leaves, 
though they differ in shape and texture, &c., are always radical, and spring 
from the upper surface around the growing point or shoot-apex, and there 
is no trace of an erect stem ; in some old bulbs two or three groups of 
leaves may be seen on the upper surface of the corm, owing to the branching 
of the originally single stem-apex. 
The Central American specimens are distinct from those of South 
America as regards their general vegetative habit, and they fall into two 
well-marked groups, in accordance with the morphological character of 
their underground tuberous portions. In one group — to which P. umbili- 
cata, , H. B. and K., P. gracillima , Wats , and P. pedicellata , Dahlst. 
(Fig. 32, PL XXX), &c., belong — there is a small smooth, more or less 
spherical underground tuber, and the roots arise from a spot on the upper 
surface to one side of the shoot-apex 2 . 
In the other group — which includes P. mexicana , Miq. (Fig. 42, 
PI. XXX), P. macrandra C. DC. (Fig. 46), &c. — there is an underground 
tuberous rhizome, which may be either short and stunted or branched and 
1 There is some difficulty with regard to Gaudichaud’s specimens collected in Peru in about 
1834, which have the number 150 and are referred both to P. peruviana and P. umbilicata 
(vide Dahlst., 1 . c., pp. 31 and 33). M. de Candolle has been good enough to send me a small 
specimen of Gaud. No. 150 from his herbarium. The roots were found to arise from the top 
of the tuber after the manner of the Mexican species (cf. P. pedicellata, Fig. 32, PI. XXX), and 
in this particular it is quite distinct from either P. peruviana, P. umbilicata , R. and P., or any other 
South American species. It thus appears that Gaud. No. 150 is either a new species for South 
America, affording a link with the Mexican forms, or that some Mexican specimens have been 
accidentally placed on the Herbarium sheets with Gaudichaud's original specimens from Peru. 
2 Cf. footnote on Gaud. No. 150. 
