(17) 
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. 
Cornus.—Calyx 4-parted. Fruit adrupe. 
Tree. Shrub. 
Eucharidium.—Calyx tube extended be- 
yond the ovary, its lobes reflexed. Pet- 
als unguiculate, lobed. Fruit a capsule. 
Gayophytum.—Calyx tube not extended 
beyond the ovary. Anthers versatile. 
Stamens alternating with staminodia, 
which are opposite to the petals. Fruit 
a capsule. 
Flowers incomplete. 
a. Perigonium inferior. 
Majanthemum.—Perigonium corolline, 
4-parted, rotate. 
Acena.—Calyx lobes valvate, tube spi- 
nose. Ovaries 1-2. Style or styles 
terminal. Fruit 1 or 2 akenes, enclosed 
in the calyx tube. 
Alchemilla.—Perigonium calycine; limb 
8-cleft. Stamens inserted on an annu- 
lar throat (faux). 
