A, ARRANGEMENT OF ORGANS. 
ment obtains in the ordinary leaves, the parts of the 
flower may be disposed according to the other method. 
In the annular disposition it generally happens that 
the rings are separated one from the other by the 
development of the stem between them, the internodes 
between the constituent leaves themselves of course 
being undeveloped ; on the other hand, in the spiral or 
successive arrangement there is no such alternate 
orowth and arrest of growth of the stem between the 
leaves, or between successive cycles, but the growth is, 
under favorable conditions,continuous—leaf is separated 
from leaf, and cycle from cycle, by the continually 
elongating stem. Thus, the two modes of growth cor- 
respond precisely with those observed in the case of 
definite and indefinite inflorescence respectively. 
The same arrangements, that are observed in the 
disposition of the leaves, apply equally well to the 
several parts of the flower; thus, in what is for con- 
venience considered the typical flower, there is a calyx 
Ce ee of five or more distinct sepals, equal 
\\ In size, and arranged in a whorl, a 
(Cp o \ ‘corolla of a nibs number of petals 
28, ) | alternating with the sepals, five 
wy, y stamens shaw: in the same position 
with reference to the petals, and 
SS five carpels alternating with the 
Fic. 1. — Diagram stamens. Throughout this book 
showing the arrange- ; : 
ment of parts inacom- this arrangement is taken as the 
ale leant ; a les standard of reference. Neverthe- 
p, petals; st, stamens; less the spiral order does occur in 
2 aaa the floral leaves as well as in those 
of the stem; it often happens, especially when the 
organs are numerous, that they form spiral series; 
5 ee 
