1879. ] Cross-Fertilization in Flowers. $ 3 
have another slight variation of the plan. The corolla tube is 
broad and large. On the upper side are the four anthers in two 
pairs, and above them, or back of them, the pistil with undivided 
stigma. Before the anthers discharge their pollen the -style is 
straight lying close to the upper side of the tube. While the 
pollen ripens and is dis- 
charging, the style elon- 
gates, and its end, after 
passing the longer sta- 
mens, turns abruptly 
downward. ‘This position 
is not usually taken till 
the pollen is all gone 
from the flower. This” Fic. 4. — Penstemon glaucus (?).. Side view. 
arrangement brings the (Natural size) 7 
stigma right in the way of any insect entering the flower, and 
scrapes from it the pollen it 
may have. received from 
some neighboring flower in 
which the stamens are dis- 
charging pollen. 
Fic, §.—Cross-sections of the same. a, Fic, 6.—Front view of the _ 
staminate stage; 4, pistillate stage. same after discharge of pollen. — 
The following table, showing relative development of pistil and : 
stamens in P, glaucus, gives full authority for the above state- _ 
ments: ` i 
: Anthers discharged Partly discharged. Closed. 
Pistils strange ee isi csc se a, o 7 2 
1. cared eS iis 21 17 pho 
It is to be regretted that the degree of curvature of the pisti : 
was not more carefully noted; it may be said, however, that 
