i68 
XEROPHYTES 
evergreen species show protections like those of winter- 
buds. 
The flowers are often produced in the dry season, or at 
the beginning of it, or during the drier parts of the wet 
season, and many have bud-protections, e.g. Eucalyptus and 
other Myrtaceae. The conspicuousness of the flower is 
often aided by, or entirely due to, the stamens, as in Acacia, 
Callistemon, &c.; there is not much risk of the pollen being 
spoiled by rain, and hence the protections found in flowers 
of wetter climates are not necessary here. Other flowers 
that freely expose their pollen are Grevillea and most other 
Proteaceae, &c. 
The seeds of many xerophytes are exposed to severe 
drought before the rains come on, and require good protec- 
tion. Those of many Proteaceae {e.g. Banksia, Xylomelum), 
of Eucalyptus, Casuarina, &c., are enclosed in hard, woody 
fruits. Many are enclosed in fruits which only open when 
wetted (the reverse of the usual behaviour, see p. 107); e.g. 
Anastatica, Mesembryanthemum, Odontospermum. The 
phenomena of germination are often interesting (p. 29). 
There are a great many species which vegetate only 
during the wet season and die down or drop their leaves in 
the dry season. Schimper terms such plants tropophytes , as 
being xerophytic at one period, and hygrophytic , i.e. living 
with plentiful water-supply, at another. Annual species, 
which exist only as seeds during the drought, are common. 
Anastatica is one of the best known. Bulbous plants are 
abundant in many of the regions mentioned above, e.g. in 
California, South Africa, &c. Other perennials have under- 
ground storage in tubers, e.g. Bowiea, Testudinaria, &c.; 
when the tuber, as in the latter genus, projects above the 
soil it is usually protected by a thick bark. Thick roots 
occur in other xerophytes. Many shrubs and trees drop 
their leaves in the dry season and store reserves to start 
growth when the rains begin. The “Catinga” forests of 
Brazil consist chiefly of species of this kind ; many Bomba- 
caceae, Jatropha, &c., are examples. They are usually well 
protected by thick bark and have deeply-penetrating roots. 
It seems probable that the autumnal defoliation of most 
trees in temperate climates is a similar case ; the soil is cold 
in winter, checking absorption, and perennials must be xero- 
