THE STEM 
45 
bearing only the flowers, as in dandelion. It may be herbaceous (not 
woody above ground), woody , succulent or fleshy ; solid , hollow ( fistular 
if herbaceous) ; straight , flexuose (zigzag), &c. ; cylindrical \ terete 
(cylindrical tapering), angular , ribbed , winged ; smooth , prickly , warty , 
hairy (for terms see Leaf, below). Polymorphism if any, form and texture 
of bud and bud-scales, growth in thickness, size and habit, bark ( smooth , 
warty , &c.), colour, and other points must also be described. 
Phyllotaxy, or the arrangement of the leaves upon the 
stem, is according to definite rules, especially in flowering- 
plants, though it varies within certain narrow limits. 
Leaves may be several at each node, when they are said 
to be in whorls , or two at each node (usually opposite ), or 
one ( alternate ). When the stem is so short that the leaves, 
as in the primrose or dandelion, are all crowded together 
and spring from the level of the ground, they are said to be 
4 radical l In the first two cases, as a rule, the leaves at 
one node stand above the gaps between those at the node 
below. In the case of alternate leaves there is found to be 
a fairly constant angle between each leaf and the next one 
above it, e.g. in Plantago (fig. 2) this angle is f- of the whole 
circumference measured the nearest way. This fraction § 
represents the phyllotaxy of the plantain. A little considera- 
tion will show that (twisting of the stem excepted) the leaves 
will stand in 8 vertical 
rows, each divided 
from the next by of 
the circumference. For 
if we start from any 
leaf 1 and pass by the 
nearest way through all 
consecutive leaves till 
we come to leaf 9, this 
must be above 1 again. 
Leaf 2 will be §, 3 will 
be -f, 4 will be -S-, 5 will 
be 6 will be 7 
will be ^ 8 -, 8 will be 
and 9 will be of the 
circumference from leaf fig. 3 phyllotaxy. 
1, i.e. immediately over 
it, and three turns of the spiral above it. Hence the rule for 
determining phyllotaxy : start from any leaf A and draw a 
