POLYPETALAE. 99 
the base only, or sessile stigmas 2 or 
more. 175. 
170 (a) Petals valvate in aestivation. 171. 
(0) Petals imbricate or contorted in aestiva- 
tion. 173. 
171 (a) Herbs or undershrubs. Seeds without 
albumen. Stem climbing or prostrate. 
Flowers unisexual. Calyx valvate or 
open in bud. Stamens as many as 
petals, or more frequently fewer. An- 
thers extrorse. Cucurbitaceae. 
(4) Shrubs or trees. Seeds with copious 
albumen. 172. 
172 (a) Leaves simple, entire dentate or lobed, 
exstipulate. Ovary 1-4-celled. Ovules 
with a lateral or dorsal raphe. Calyx 
valvate or open in bud. Stamens as 
many as petals or more. Anthers 
dehiscing introrsely or laterally. 
Cornaceae. 
(2) Leaves compound, rarely simple, but 
then ovary 5- or more-celled and leaves 
usually stipulate. Ovules with a ventral 
raphe. Calyx-limb short or scarcely 
perceptible. Stamens as many as petals. 
Aralvaceae. 
173 (a) Segments of the calyx 2-4, valvate in 
