— 
lodged must strike ¢ 
206 BOTANICAL GAZETTE. [ August, 
can see, therefore, how an abortion of the lower nectaries 
would be advantageous. 
In the insect relations of this flower we find the conditions 
which have given rise to more complicated forms, and whic 
may still further modify the Hibiscus. 
When a flower with a single”central nectary becomes hor- 
izontal, its new position makes access to the nectary useless, 
except on the upper side, and this makes possible different 
modifications of the lower parts, which make the nectar in- 
accessible except above. In many Papilionacee, for exam- 
ple, nine lower stamens are united, leaving a way to the 
nectar only on the upper side 
en the flower turns to an horizontal position, the effect 
on the petals is to deprive them of their function as a landing, 
and this makes possible many specializations for other pur- 
oses. 
i Ss Papilionacee two lower petals are united, formas 
'gnting-plate for insects, increasing the attractiveness © : 
; 4 Ower, protecting the stamens from rain and fr om po ih 
eating intruders, and enabling them to strike the visitor WI 
more precision!7, 
18 For illustration of foaest ; Il. : 
WWhite ancr ot * Gaura Lindheimeri, see Wild Flowers of Am., pl. aay so, iD 
Phaseolus the keel eur ionaceze are sternotribe, and all were no doubt ae r pleuro- 
tribe™ In Ani eel guides the stamens against the insect’s side, making the od when dis" 
rtrike Gui Of the keel is fixed to the summit of the banner, a : 
he inseet’s back, making the flower nototribe. 
