CHAP. II. 
LEAVES. 
93 
number of scales or parts that constitute it. Thus 2t indicates 
that eight turns are made round the axis before any scale or 
part is exactly vertical to that which was first formed, and the 
number of scales or parts that intervene before this coincidence 
takes place is 21. 
The following are some of the results thus obtained by 
Braun, in studying the composition of the spires of different 
plants : — 
i in Asarum, Aristolochia, Lime tree, Vetch, Pea, the spikes 
of all grasses. 
i is rare in Diotyledons, and generally changes into more 
complicated spires. It exists in Cactus speciosus, and some 
others. 
f is the most common of all, and represents the quincunx. 
Mezereum, Lapsana communis, Polemonium coeruleum, 
Potato, are examples. 
% is also common, as in the Bay-tree, the Holly, common 
Aconite, and the tuft of radical leaves of Plantago media. 
tV exists where the leaves are numerous and their intervals 
small. Wormwood, common Arbutus, dwarf Convolvulus, and 
the tufts of leaves in London Pride and Dandelion, are in- 
stances. 
in Woad, Plantago laneeolata, the bracts of Digitalis 
lanata. 
in Sempervivum arboreum, the bracts of Plantago media, 
and of Protea argentea. 
1^ was found on an old trunk of Zamia horrida, and ten 
species of Cactus (coronarius and difformis). 
It does not, however, appear that this inquiry has led to 
any thing beyond the establishment of the fact, that, beginning 
from the cotyledons, the whole of the appendages of the axis 
of plants — leaves, calyx, corolla, stamens, and carpels — form 
an uninterrupted spire, governed by laws which are nearly 
constant. No application of the doctrine appears practicable, 
except to assist in the distinction of species, for which it would 
be well adapted, if the determination of the series with the 
requisite precision were less difficult ; this is shown in the fol- 
lowing instances of differences in the fundamental spire in 
nearly allied species. 
