80 _ ELEMENTARY BOTANY 
Floral formula: K2+2, Cx 4, A2+4 22, GQ), 7 
The x before the 4 denotes that the petals are in the 
diagonal plane. The four large stamens are expressed by the 
formula 2? to show that they belong to the same whorl, and — 
have probably arisen from two stamens. One reason for 
this theory. of the structure of the Wallflower is that the 
Fumariacee, an Order closely allied to the Crucifers, have the 
stamens arranged in two groups. 
Gharae. This Order is easily distinguished from all 
teristics. others by the number of its petals, stamens, 
and carpels ; but the different genera are only determined by 
a minute examination of the fruit and seed. | 
Many plants are articles of food, thus the roots of the radish 
and turnip, the primary shoots of the cabbage are eaten, 
whilst the buds in the leaf axils of the same species form 
~ Brussels sprouts. In the cauliflower, the inflorescence ; and 
in mustard and cress, the cotyledons are articles of food. 
The fruit of the Crucifere is either a siliqua or silicula. 
Shepherd’s purse, Honesty, Pennycress, are, perhaps, the best 
known examples of the latter. 
All over the world, but scarce in the tropics. 
Wallflower and Alyssum, so abundant in English 
gardens, are not found in‘those of tropical regions. 
Distribution. 
CARYOPHYLLACEA (the Pink Family). 
STELLARIA HoLosTEA (Great Starwort or 
Stitchwort). 
A perennial herb, with opposite, sessile leaves. 
Inflorescence: a two-sided cyme (Fig. 53). 
Flowers : regular and hypogynous (Figs. 67, 68). 
Calyx (sepals): 5, free, inferior. 
Corolla (petals): 5, free, hypogynous. Each petal is deeply 
indented. 7 
Andrecium (stamens): 10, free, hypogynous ; in two whorls. 
Gynecium (carpels) : 3, joined, superior ; ovary one-celled. 
Fruit: a capsule dehiscing by six teeth. The fruit of 
the Stellaria resembles that of the Lychnis (Fig. 80), except 
that the latter dehisces by ten teeth instead of six, as it is 
Type. 
