38 
BULLETIN OF WISCONSIN NATURAL HISTORY SOCIETY. VOL. 5, NO. 1. 
the four perianth-leaves of 3 mm. length become strongly reflsxed, 
and the four stamens which are only 2 mm. long move outwards. 
The two divisions of the pistil are connected nearly for their entire 
length, but the stigma is two-parted. The latter is already recep- 
tive at the time the flowers open, and the introrse anthers begin 
to dehisce shortly afterward. Proterogyny is therefore short- 
lived. On account of the vertical position of the flowers pollen 
is more liable to fall on the stigma of the same flower and produce 
spontaneous self-pollination then in any of the species of Vaguer a 
dealt with above. No nectar is present, but the flowers receive 
sufficient attention from short-tongued bees and flies to effect 
cross-pollination in many instances. In the following I present 
the list of visitors observed on the flowers : 
A. Hymenoptera 
Andrenidae: (i) Halicfus prozancheri D. T., female, c. p.; (2) 
H. leronxii Lep., female, c. p. 
B. Diptera 
Culicidce: (3) Ciilex sthmilans ^■2^k.\ Syrphidae : (4) Meso- 
gramma geminata Say; (5) Neoascia globosa Walk.; (6) Mallota 
posticata Pabr.; Conopidse : (7) Zodion fiilvifrons Say — all except 
(3) and (7) f. p. 
C. Coleoptera, 
Cerambvcidai : (8) Cyrtophorus verrucosus Oliv. ; Chry- 
somelidae: (9) Crepidodera cucuineris Harr. — both f. p. 
Streptopus roseus Mich. Sessile-leaved Twisted-stalk. 
This species has a rather short blooming time, viz : from about 
May 23 to June 7. None of the specimens under observation were 
higher than 4 dm., and while the smaller plants have simple stems 
the larger ones carry one or two branches in addition to the main 
stem. The slender pedicel of ij/i cm. length is bent downward 
under the corresponding stem-leaf, and carries a rose-colored 
pendulous and bell-shaped flower. The position of the latter under 
the nearly horizontal stem-leaf hides it from view from 
above, and also aff'ords it some protection from the rain and the 
rays of the sun. There is an overlapping of the three perianth- 
leaves of the outer row and those of the inner row, whereby a 
tube is formed 8 mm. in length with reflexed tips. Each leaf of 
