(17) 



2. Ptelea. Stamens alternating with the 

 petals. Ovary on a convex disc, 2-celled. 

 Cells 2-ovulate. Fruit a 2-seeded sa- 

 mara. Shrub. 



e. Corolla 4-petalous, superior. 



1. Cornus. Calyx 4-parted. Fruit adrupe. 

 Tree. Shrub. 



2. Eucharidium. Calyx tube extended be- 

 yond the ovary, its lobes reflexed. Pet- 

 als unguiculate, lobed. Fruit a capsule. 



3. Gayophytum. Calyx tube not extended 

 beyond the ovary. Anthers versatile. 

 Stamens alternating with staminodia, 

 which are opposite to the petals. Fruit 

 a capsule. 



B. Flowers incomplete. 



a. Perigonium inferior. 



1. Majanthemum. Perigonium corolline, 

 4-parted, rotate. 



2. Acsena. Calyx lobes valvate, tube spi- 

 nose. Ovaries 1-2. Style or styles 

 terminal. Fruit 1 or 2 akenes, enclosed 

 in the calyx tube. 



3. Alchemilla. Perigonium calycine; limb 

 8-cleft. Stamens inserted on an annu- 

 lar throat (faux). 



