Ixxil INTRODUCTION. 
Male flowers in globular heads ina terminalraceme. Females 
133) ®Xillary, joined two together in a large prickly burr, with 
incurved points. . XANTHTIUM (p. 235). 
Flowers, male and female, distinct, or in heads, not prickly . 134 
134 perianth of 4 parts . : ; : 135 
Male perianth of 5 or 3 parts . | CHENOPODIACER (p. 370). 
Leaves all radical, linear and fleshy, or transparent. Marsh 
135 or water plants . . ‘ : ; . 136 
Stems leafy. Leaves flat . ; URTICACEA (p. 398). 
Male flowers one or two ona stalk, ‘with very long stamens. 
136) ._Females sessile. . LITTORELLA (p. 367). 
Male and female flowers minute, mixed together in a small 
terminal head : ; : : . ERIOCAULON (p. 476). 
137 “clea opposite, simple . : : . MERCURIALIS (p. 395). 
Leaves alternate, pinnate . : POTERIUM (p. 141). - 
Leaves alternate, with sheathing stipules. Stamens 6. Nut 
enclosed in the calyx. : . RUMEX (p. 879). 
Leaves small and fine, in tufts. Stamens 6. Fruita berry 
138 ASPARAGUS (p. 459). 
Leaves small and heath-like. Stamens 3. Fruit a berry 
EMPETRUM (p. 396). 
Leaves radical, long, arrow-shaped. Stamens and carpels 
numerous. Aquatic plant . : . SAGITTARTIA (p. 431). 
139 Flowers all male (a male specimen) . 2 ‘ t ‘ » Ler 
Flowers all female (a female specimen) . : 140, 
Perianth 6-cleft, the 3 inner segments larger. " Styles 3, with 
short fringed stigmas. Leaves alternate or radical. 
3 RUMEX (p. 379). 
1404 Perianth 2- or 4-cleft. Stigma single, sail tufted. Leaves 
opposite, stinging . . URTICA,(p. 399) 
Perianth 3-cleft. Styles 2, simple. Leaves opposite, not sting- 
ing. ; : : . MERCURIALIS (p. 395), 
3. Trees or Shrubs. 
ie a opposite . : ; : : : : . 142 
Leaves alternate or in tufts : : : . 145 
149 Leaves divided, lobed or angular, deciduous F : ; . 143: 
Leaves entire, evergreen . : : : . 144 
Leaves lobed or angular. Stamens about 8, Fruit with two 
143 diverging wings. bos . ACER (p. 96). 
Leaves pinnate. Stamens in pairs, collected in clusters. Fruit 
with one erect wing. i FRAXINUS (p. 297). 
Parasitical shrub with green dichotomous stems. Fruita berry 
144 VISCUM (p. 204). 
Erect branching shrub with shining leaves. Fruit a few- 
seeded capsule : .  BUxXuUS (p. 396). 
Male flowers in catkins, separated by scales only. Females 
solitary or in clusters, or in catkins, usually different from 
the males : 146. 
Flowers hermaphrodite or diclinous, each with a distinct 
perianth : ‘ ‘ é , ; ‘ : : . 147 
145 
