ii8 
PHARMACEUTICAL BOTANY 
two motions, the circular and the longitudinal, and its most common 
modification is the circle. 
In the alternate arrangement there is but one leaf produced at 
each node. 
Opposite, when a pair of leaves is developed at each node, on 
opposite sides of the stem. Example: Mints, Lilac. 
Decussate, when the leaves are arranged in pairs successively 
along the stem, at right angles to each other. 
Whorled or Verticillate, when three or more form a circle about 
the stem. Example: Canada Lily and Culver’s root. 
Fascicled or T ufted, when a cluster of leaves is borne from a single 
node, as in the Larch and Pine. 
The spiral arrangement is said to be two-ranked when the third 
leaf is over the first, as in all Grasses; three-ranked, when the fourth 
is over the first. Example: Sedges. The five-ranked arrangement 
is the most common, and in this the sixth leaf is directly over the 
first, two turns being made around the stem to reach it. Example: 
Cherry, Apple, Peach, Oak and Willow, etc. As the distance be- 
tween any two leaves is two-fifths of the circumference of the stem, 
the five-ranked arrangement is expressed by the fraction In 
the eight-ranked arrangement the ninth leaf stands over the first, 
and three turns are required to reach it, hence the fraction % ex- 
presses it. Of the series of fractions thus obtained, the numerator 
represents the number of turns 
to complete a cycle, or to reach 
the leaf which is directly over 
the first; the denominator, the 
number of perpendicular rows 
on the stem, or the number of 
leaves, counting along thd 
spiral, from any one to the one 
directly above it. 
Vernation.- — Prefoliation or Vernation relates to the way in which 
leaves are disposed in the bud. A study of the individual leaf 
enables us to distinguish the following forms. When the apex is bent 
inward toward the base, as in the leaf of the Tulip Tree, it is said to be 
inflexed or reclinate vernation; if doubled on the midrib so that 
convolute 
Fig. 54- — Three principal types of verna- 
tion. (Robbins.) 
