42 BOTANICAL GAZETT [JULY 
specialized nectaries and precise localization of pollen contact. 
'In the less specialized plants, this kind of adaptation early 
reached the highest degree of perfection in the case of the 
orchids. But, as far as I know, no orchid holds an important 
relation in the economy of any bee. 
Under the influence of the female bees, the most highly spe- 
cialized of anthophilous insects, the highest development is 
found in homogamous flowers without nectar, such as Desmodium 
and Cassia. 
Since bees have entered the field, many flowers seem to have 
been at a disadvantage in gaining their services, because the sta- 
mens were so few that they could not offer pollen in paying 
quantities. And in many cases the stamens were covered by 
gale and carina, so that, to collect the pollen, the bee would 
have to spend much time going to the bottom of every flower. 
This difficulty was obviated by lengthening the stamens, reduc- 
ing the size of the flowers, and crowding the flowers so that the 
bees could run over or around the inflorescences and sweep Up 
immense quantities of pollen. Inflorescences of this kind are 
found in Cornus, Hydrangea and Viburnum. 
Here we find an explanation of the fact that certain Legt- 
minose and Labiate have abandoned their galez and caring, 
exposing their stamens, and contracting their infloresences into 
head-like or flat-topped clusters, as in Amorpha, Petalostemom, 
Lophanthus, Mentha, Blephilia, and Pycnanthemum. Contraty 
to Miiller, I think Delpino is right in regarding Mentha as one — 
of the most highly specialized of the Labiate, and I incline to 
the same opinion regarding the above genera of Leguminos® — 
These cases are obscured by the fact that the arrangements per “ 
mit the visits of a lot of less specialized insects. Nevertheles* 
I think the bees have determined the result. 
In the case of Lobelia I have mentioned that small bees col 
lect the pollen pushed out of the tube before the stigma appears. 
In the Composite we find plants perhaps best adapted to attract 
and utilize the pollen-collecting bees, and the table shows that 
they have among their visitors more oligotropic. bees than any 
ei ee Ss le AS a 
