PO PE ee 
1893.) Flowers and Insects. 47 
and we find that the cortex cells are round and have many 
spaces between the cells, while fig. 19 represents the roots 
of Actea alba, which grows on dry banks, and here the cor- 
tex cells are angular and the spaces between cells are almost 
none. The differences in vascular development are also well 
shown in these figures. 
In this part of the paper I have not discussed the general 
structure of the species studied as regards the occurrence and 
distribution of the histological elements, since I find that Ma- 
rie, Hegelmaier, and others have described the general struc- 
ture of many species of Ranunculacee, and in many cases my 
descriptions would have been but a repetition of theirs. 
University of Chicago. 
Flowers and insects. X. 
CHARLES ROBERTSON. 
STEIRONEMA LANCEOLATUM Gray.— The plants are com- 
monly collected in small patches. They grow 3 or 4™ high, 
and expose a few yellow flowers with reddish-purple centers. 
The flowers: look outwards and a little downwards, and ex- 
pand from 20 to 25™". In the bud each corolla lobe en- 
folds an anther. When the flower expands, the lobes carry 
the enclosed anthers with them, holding them while the 
stigma is receptive and is exposed to insects—a fact to which 
my attention was first called by Professor Pammel. After 
the anthers are released, the styles are commonly found bent 
outwards, out of the way of the falling pollen. Sprengel sup- 
posed that flowers of Lystmachia quadrifolia were nectar 
bearing, but failed to find nectar. He, and Miiller also, failed 
to find honey in flowers of L. vulgaris. According to Kirch- 
ner nectar is wanting in L. zemorum as well as in L. nummul- 
arta. J have been uncertain in regard to the occurrence of 
honey in Steironema, but the visits of male bees seem to in- 
dicate its presence, although these insects might search for it 
in vain. They commonly fly about the flowers to find the 
females, not trying to find honey. 
have noted the flowers in bloom from June 20th to July 
12th. As far as I have observed, they are visited for honey 
and pollen only by Macropis steironematis Rob. 89. 
