124 KEY AND FLORA 
3. R. Woodsii Lindl. Stems 3-36 in. high, with slender spines which 
are often wanting above. Stipules rather broad, entire; leaflets usu- 
ally 5-7, varying from obovate to lanceolate, rather obtuse at the apex, 
narrowed at the base, somewhat serrate. Flowers corymbed or solitary, 
Sepals erect on the globose or somewhat ovoid fruit. Prairies W. 
4. R. rubiginosa L. SweeTBRIER. Stem erect or curving, armed 
with stout recurved prickles. Leaves with 5-7 leaflets, the latter 
broadly oval, coarsely serrate, glandular-bristly beneath, aromatic. 
Flowers white or pink. Sepals widely spreading, deciduous. Fruit 
obovate, slightly bristly. Common in cultivation and sometimes wild.* 
5. R. carolina L. Swamp Rose. Stems 4-8 ft. high, with stout 
and generally recurved prickles. Stipules long and narrow ; leaflets 
commonly downy beneath, finely serrate. Flowers several in a ‘corymb, 
bright rose color. Sepals spreading and falling off after flowering. 
Damp woods and borders of swamps. 
6. R. virginiana Mill. Dwarr Witp Roses. Stems varying in 
height from less than a foot to 6 ft., with stout, somewhat hooked 
prickles. Stipules rather broad; leaflets small, thickish and glossy 
above, coarsely toothed toward ‘the tip. Flowers corymbed or soli- 
tary, pale rose color. Sepals spreading and falling off after flowering. 
Moist ground and swamps. ‘ 
7. R. humilis Marsh. Pasture Ross. Stem erect, branched, 
usually armed with stout stipular prickles and with bristles, but 
sometimes nearly smooth, 1-3 ft. tall. Leaves mostly of 5 leaflets; 
stipules entire; leaflets oblong-lanceolate or oval, shining above, 
pale beneath, sharply serrate. Flowers solitary or 2-3 together, 
2-3 in. broad, pink. Peduncles and calyx glandular-downy. Sepals 
leaf-like, spreading, finally deciduous. Styles distinct. Fruit globose, 
bristly-hairy. On dry soil; our most common wild rose. 8.* 
XIV. PRUNUS L. 
Trees or shrubs. Leaves simple, with stipules, which are 
often small or fall off early. Calyx with a bell-shaped or urn- 
shaped tube and 5-lobed spreading limb, falling off after flower- 
ing. Petals 5; stamens 3-5 times as numerous, or indefinite, 
inserted on the throat of the calyx tube. Pistil 1, long-styled, 
with 2 ovules, ripening into a single drupe. 
B. Fl. species 8 (Amygdalus). 
A. Stone more or less spherical ; fruit smooth when ripe. Branches 
not spiny. (Cherries.) 
1. P. serotina Ehrh. Wizp Brack Cuerry. Often becoming a 
large tree; bark on old trees rough, nearly black. Leaves rather 
