1907.] 
Graemclier, PoUiuation of Wisconsin Flotvers. 
87 
genera Halictits and Augochlora also resort to these flowers in 
search of pollen, as shown by the heavy and very conspicuous 
load of brick-red pollen that they carry away. The earliest 
flowers of Hcuchcra hispida make their appearance several days 
ahead of their special pollinator Collcfes wstiz'alis. In 1901, for 
example, the first flowers were noticed on June 7. On June 11 
the females of Halictus and Augochlora were busy at these 
flowers, but of Colletes a single specimen was seen, a male flying 
around the flowers in search of the females, which had not arrived 
up to this time. Four days later, however, (at the time of my 
next visit) they were also present, sucking and collecting pollen. 
Judging from the description of the flowers as given by Robertson, 
those of our surroundings agree essentially with those from South- 
ern Illinois. The inflorescence is a panicle containing numerous 
greenish tubular flowers, which have been observed in blossom 
from June 3 to July 2. Along its upper side the flower is longer 
than along the lower side ; in other words, it is obliquely cut off, 
and the width of 4 mm. end;bles the visiting short-tongued bees to 
insert their heads into the tube in search of nectar at the bottom. 
The tube is 6 mm. long, and nectar is secreted in drops on the 
upper surface of the ovary and on the adjacent walls of the calyx. 
These flowers are proterogynous, but the upper anthers shed their 
pollen soon after the stigmas have become receptive. The two 
divergent styles, with their small stigmas, reach the mouth of the 
flower, but since the dehiscent anthers are situated 2 or 3 mm. 
beyond the mouth of the flower, spontaneous self-pollination can 
jiardly be expected to take place in the nodding flower. As a rule, 
the flowers are visited early before their anthers begin to open, and 
this insures cross-pollination. The following bees were taken on 
the flowers : 
Andrenidae: (i) Colletes wstivalis, Patton, male and female, 
s. and c. p. ; (2) Halictus provancheri D. T., female, s. and c. p. ; 
(3) H. sephyrus Sm., female, s. and c. p. ; (4) H. hortensis Lov., 
female, s. and c. p.; (5) Augochlora confiisa Rob., female, 
s. and c. p. 
