16 CLASS-BOOK OF BOTANY. 
CHAPTER Il. 
——————— 
2. Tus WaLLFLOWER (Chetranthus cheiri). 
Tue plants which you have hitherto examined have beén on 
the whole apparently rather diverse from one another, and yet 
they show a remarkable similarity in certain points. Thus, in 
their flowers there are usually 5 free inferior sepals, 5 free 
hypogynous petals, co free hypogynous stamens with adnate 
anthers, and seeds with small embryos in a large quantity of 
albumen. There are also other points in which they re- 
semble each other more or less. Those now to be examined 
are different in many of their characters from those of the 
previous group, but show a still closer agreement with one 
another. We may take the Wallflower as a type, as it is to be 
found in nearly every garden. 
The plant is an erect herb, so woody in the stem as 
almost to be termed shrubby; its leaves are simple, about 
lanceolate-oblong in shape, and usually entire in their margins. 
The arrangement of the flowers is very distinct: each flower 
is on a short pedicel, and these pedicels are arranged alter- 
nately along a common peduncle or rachis.* The lowest 
flowers are the first to open, and the rachis goes on lengthen- 
ing and producing flowers as long as the plant continues to 
grow freely. Any inflorescence in which the lowest or outer- 
most flowers of a cluster open first is said to be indefinite, 
and this particular form in which the flowers are on 
pedicels arranged along a rachis is called a raceme. 
Notice that each flower has 4 inferior sepals, 4 hypo- 
gynous petals, 6 hypogynous stamens, and an elongated 
superior ovary in the centre. The sepals are slightly pouched 
(saccate}) at their base, and are very deciduous}—1.e., they 
fall off readily after the flowers have been open for a day or 
two. Hach petal has along narrow lower portion, or claw, 
and a spread-out blade, or limb, and the whole four petals 
stand crosswise. The stamens are in two rows, two of them 
being placed lower down in the outer row, and four standing 
higher in the inner row, and at right angles to the others. The 
anthers therefore appear to be at different levels; and this 
arrangement of 6 free stamens—vyiz., 4 long and 2 short—is 
* Gr, rhachis, the back-bone. + Lat. saccus, a sac or pouch. 
; Lat. de, down; cado, I fall. 
