THE FLOWER 217 
organization are characterized by having their organs free 
and hypogynous, while the more highly developed forms show 
a tendency to consolidation and union of parts, and the 
epigynous mode of 
insertion. Irregular- 
ity also, since it in- 
dicates specialization 
and adaptation to a 
particular purpose, 
may be regarded as a 
mark of advanced 
evolution. 
243. Dissection of 
a bilabiate flower. — 
Make a similar study 
of the flower of a 
salvia, dead netile, Fics. 323, 324.—Salvia: 323, a newly opened 
flower, showing the pollen-covered anther striking 
catalpa, or other spec- the back of a visiting bee; 324, an older flower, 
imen of the bilabiate with the protruding pistil rubbing against the back 
ein a ‘Mule diagrams of a bee covered with pollen from a younger flower. 
and report as to (1) numerical plan; (2) presence or absence 
of parts; (3) regularity; (4) union of parts; (5) position of 
ovary. Observe especially the relative position of stigma 
Figs. 325, 326.—Salvia: 325, longitudinal section through a flower, showing 
the rocking connective which is struck at a by a visiting insect; 326, section of the 
same flower after being visited, showing the lower arm of the connective pushed 
back and lowering the anther. 
and anthers; is it such that the pollen can reach the stigma 
without external aid? Does the peculiar shape of the corolla 
serve any other purpose than to attract the attention of 
