Ixxu INTRODUCTION. 
| Male flowers in globular heads in a terminal raceme, Females 
axillary, joined two together in a at prickly burr, witk in- 
ea curved points . : XANTHIUM (p. 236.) 
| Flowers, male and female, distinct, or in heads, not prickly . 134 
134 ‘Atle perianth of 4 parts. ; ; : 135 
. Male perianth of 5 or 3 parts’. : CHENOPODIACES (p. 371. ) 
Leaves all radical, linear and fleshy, or transparent. Marsh or 
195) water plants . : ‘ is 5 ; . . 136 
Stems leafy. Leaves flat . ; URTICCAER (p. 398.) 
Male flowers one or two on a stalk, with very long stamens. 
13 | Females sessile , .  LITTORELLA (p. 368.) 
Male and female flowers minute, “mixed together in a small ter- 
minal head. . 5 : .- .  ERIOCAULON (p. 474.) 
137 { Leaves opposite, simple : : : . MERCURIALIS (p. 395.) 
\ Leaves alternate, pinnate . ; PoTERIvUM (p. 141.) 
{ Leaves alternate, with sheathing stipules. Stamens 6. Nut en- 
closed in the calyx . . - ,.  RuMEX (p. 379.) 
| Leaves small and fine, in tufts. Sencar = Fruit a berry. 
AsPREnae (p. 458.) 
ae ‘Leaves small and heath-like. Stamens 3. Fruit a berry. 
EMPETRUM (p. 397.) 
Leaves radical, long, arrow-shaped. Stamens and carpels nu- 
merous. Aquatic plant . : : SAGITTARIA (p. 429.) 
139: f Flowers all male (a male specimen) . : . 180 
(Flowers all female (a female specimen) 140 
Perianth 6-cleft, the 3 inner segments larger. Styles = with 
short fringed stigmas. Leaves alternate or radical. 
RuMEX (p. 379.) 
140< Perianth 2- or 4-cleft. ie ae oo sessile, tufted. Leaves 
opposite, stinging . ; Urtica (p. 399.) 
Perianth 3-cleft. Styles 2, simple. Leaves opposite, not sting- 
uniey italy : MERCURIALIS (p. 395.) 
3. Trees or Shrubs. 
141- _{ Leaves opposite . : : : ; . 142 
| Leaves alternate or in eatee ‘ ; Q . 145 
149J Leaves divided, lobed or angular, deciduous ; : : . 148 
Leaves entire, evergreen. é 2 . 144 
i Leaves lobed or angular. Stamens about 8. Fruit with two 
1432 . diverging wings. . ACER (p. 97.) 
Leaves pinnate. Stamens in pairs, collected in clusters. Fruit 
with one erect wing ; : . FRAXINUS (p. 298.) 
Parasitical shrub with green dichotomous stems. Fruit a berry. 
Viscum (p. 205.) 
Erect branching shrub with shining leaves. Fruit a few-seeded ) 
capsule . : ; Buxus (p. 396.) 
Male flowers in catkins, separ ated “by scales only. Females 
1452 Solitary or in clusters, or in catkins, usually different from the 
males . : 146 
Flowers hermaphr odite or diclinous, each with a distinct perianth 147. 
144 
