Viola palmata and its allies 
Ezra BRAINERD 
(WITH PLATE 36) 
Of the 54 species, as I understand them, of North American 
violets east of the tooth meridian, 28 (or over one half) are of the 
class familiarly known as “blue stemless violets’; and of these 
28 species 13 belong to a natural group represented by the widely 
distributed Viola palmata and V. papilionacea. The group is well 
characterized by having its cleistogamous flowers on short pros- 
trate peduncles, often concealed under dead leaves or soil; as a 
rule the leaves are reniform in outline, the spurred petal glabrous 
or nearly so, the auricles of the sepals short and appressed, and 
the cleistogamous capsules purplish or flecked with purple. 
The group is readily subdivided into species that have lobed 
or parted leaves, and species that do not. The cut-leaved species, 
of which there are six, have been greatly confused from the time 
‘when V. palmata was first described and figured by Plukenet in 
-1692 till the present. This may be, in part, because they have 
their fullest development in the South, where the genus has been 
of late less critically studied than in the North and West. But it 
is also quite evident that both past and present botanists have 
been perplexed and misled by the frequent occurrence of aberrant _ 
forms that have arisen from the crossing of V. palmata and V, 
triloba with each other and with allied species. 
The cut-leaved species may be separated into two radically 
distinct subgroups represented by Viola palmata and V. triloba, 
and differing as follows: 
A. In the palmata subgroup uncut leaves are rare, af not alto- 
gether wanting; in the triloba subgroup they are frequent, the first 
one or two leaves of spring and the leaves of late summer being 
generally uncut. In other words, the latter subgroup is strictly 
heterophyllous; the former subgroup, homophyllous. 
B. In the palmata subgroup the leaves are palmately cut; in the 
triloba subgroup the leaves are pedately cut. In all cut-leaved 
species of Viola the primary cutting is ternate, as in Trifolium. 
581 
sation 
Bt 
