
118 FLOWERING PLANTS 
through the adaptation of these organs that they are able 
to live in such a variety of habitat. The majority are herba- 
ceous, mesophytic plants. Hydrophytes and Epiphytes are 
. Tare ; 80, too, are shrubs and trees ; but, curiously enough, these 
last are plentiful in the Composite flora of oceanic islands. 
On the whole the Order is markedly xerophytic in char- 
acter, as the following genera show. 
Sea Aster has fleshy leaves, and grows on the coasts. 
Cudweed (Gnaphalium) is an alpine plant, found chiefly in 
Scotland, and is more or less covered with cottony wool. 
Antennaria is found chiefly on the hills of the seashores, and 
is also woolly. Many of our Hawkweeds have the hairiness 
characteristic of xerophytes. One of the most markedly 
xerophytic plants of the Order is the Compass plant:(Silphium) 
of the prairies, which turns the edges of its leaves to north 
and south, so as to avoid the excessive mid-day sun. 
The genus Senecio is particularly interesting, for it has 
_ plants of the most various habit ; on the whole it is xerophytic. 
Many species are hairy, and have fleshy leaves. Senecio viscosus 
has leaves capable of inrolling. | 
The common Daisy (Bellis perennis) and the “ Weather 
Thistle of the Alps” (Carlina acaulis) show special adaptations 
for protection from weather. The Daisy closes at night and 
in wet weather; whilst in the Thistle the outer bracts are 
prickly, the inner membranous and shining ; they spread out 
like a star in dry air, but in damp weather they bend inwards 
over the flower-head. 
PRIMULACE. 
Character. “iil the plants belonging to this Order are herbs, 
istics of the and the number of floral leaves is usually 5. 
Order. The stamens are opposite to, not alternate with, 
the petals; this is easily seen in the Primrose, but not so 
easily in the genus Lysimachia. The placentation is free 
central, the fruit is a capsule. 
| The genus Primula has already been described 
(“Elementary Botany,” p. 93) ; the following may 
here be noticed : . 
Genera. 


