JAN. 1907. 
WISCONSIN FLOWERS AND THEIR POLLINATION. 
29 
on one side of the flower and crawls around between the stamens 
and the perianth-leaves, draining one nectary after the other, and 
thereby dusting the lower surface of its front wings with pollen. 
Incidentally it rubs these same parts against the stigma. One bee 
and three butterflies make up the list of visitors : 
A. Hymenoptera 
Andrenidae: (i) Augochlora confiisa Rob. female, c. p. 
B. Lepidoptera 
Rhopalocera : (2) Papilio polyxenes Fabr. ; (3) Argynnis 
cybele Fabr.; (4) Phyciodes tharos Dru. — all s. 
Erythronium albidum Nutt. White Adder's Tongne. White Dog-'s 
tooth Violet. 
This plant has been found in bloom from April 20 to May 15. 
Robertson (9) has given an account of this species and from this 
we see that there is a considerable difiference in size between the 
flowers of our region with a diameter of 3 to 4 cm., and those 
of southern Illinois with a diameter of 6y^ cm. There is a soli- 
tary nodding white flower at the end of a scape of about 12 cm. 
length. Each of the three inner perianth-leaves has a pit-shaped 
nectary near the base and a small furrow running down to the 
latter. The adjoining filament covers the furrow^ from within, and 
the proboscis of an insect has to pass through the canal thus 
formed in order to obtain nectar. There is a median yellow spot, a 
''nectar-guide" near the base of each of the perianth-leaves, and 
it is of a deeper color and more distinctly heart-shaped on the 
inner ones. The stamens of the outer row are shorter than the 
others on account of the shorter anthers, and they shed their 
pollen entirely before those of the inner row start to dehisce. The 
flowers are homogamous since the stigma matures together with 
the outer anthers. As a rule the stigma in this species has three 
long and spreading branches, while that of B. Americanum the 
second species of our flora is usually short and simple. But 
Meads ( 10) has shown that there exists a great amount of vari- 
9. Chas. Eobertson. " Flowers and insects VIII. Bot. Gaz., Vol. 
XVII., pp. 69-71 (1892). 
10. M. E. Meads. The range of variation in species of Erythro- 
nium. Bot. Gaz., Vol. XVIII., p. 134 (1893). 
