SHOOTS 
79 
nation and seed-distribution. 
It is necessary to call attention 
to certain peculiar features of 
this type of stem. 
56. Structures. The joints 
of the stem do not spread 
apart, so that the peculiar 
leaves are kept close together, 
usually forming a rosette-like 
cluster (see Fig. 71). These 
leaves are of four kinds : the 
lowest (outermost) ones (indi- 
vidually sepals, collectively 
calyx} mostly resemble small 
foliage leaves ; the next higher 
(inner) set (individually petals, 
collectively corolla) are usually 
the most conspicuous, delicate 
in texture and brightly col- 
ored ; the third set (stamens) 
produces the pollen ; the 
highest (innermost) set (car- 
pels) form the pistil and pro- 
duce the ovules, which are to 
become seeds. These four sets 
may not all be present in the 
same flower ; the members of 
the same set may be more or 
less blended with one another, 
forming tubes, urns, etc. (see 
Figs. 72, 73, 74) ; or the dif- 
ferent members may be modi- 
fied in the greatest variety of 
ways. 
Another peculiarity of this 
type of stem is that when the 
FIG. 72. A group of flowers of the rose 
family. The one at the top (Poten- 
lilld) shows three broad sepals, 
much smaller petals alternating 
with them, a group of stamens, and 
a large receptacle bearing numer- 
ous small carpels. The central one 
(Alchemilld) shows the tips of two 
small sepals, three larger petals 
united below, stamens arising from 
the rim of the urn, and a single pe- 
culiar pistil. The lowest flower (the 
common apple) shows the sepals, 
petals, stamens, and three styles, 
all arising from the ovary part of 
the pistil. After FOCKE. 
