OUTLINES OF BOTANY. 
XXI 
Iris (p. 482) and all Grasses. They are often 3- ranked or trislichous (£), as 
in White Hellebore (p. 600), and in Sedges (p. 535), when the fourth comes 
over the first, the fifth over the second, the sixth over the third, and so on. 
In the next case, which prevails in Exogens, they are 5-ranked or quincun- 
cial (|), the spirally ascending line drawn to connect the insertions of ad¬ 
jacent leaves making two revolutions round the stem to reach the sixth 
leaf, which stands over the first, the seventh standing over the second, the 
eighth over the third, and so on, the angular distance between any two 
leaves in succession being two-fifths of the circumference. In the case 
next in order the leaves are 8 -ranked (f), as in the Plum, the ninth leaf be¬ 
ing over the first, and three turns round the stem being made to reach it. 
Next they are 13 -ranked (^), as in the Ailanthus (p. 78), and the four¬ 
teenth leaf covers the first, five turns round the stem being made to 
reach it. 
88 . The pairs of opposite leaves follow similar orders of arrangement. 
89. When the pairs ctoss each other exactly at right angles, so as to 
form four straight ranks of leaves (as in the Mint Family, p. 313), they are 
said to be decussate. 
90. Only one leaf springs from the same point. Fascicled or chattered 
leaves, which often appear to form an exception (as in the Pine, p. 439, 
and Larch, p. 442), are those of a whole branch, developed without any 
obvious elongation of the internodes so as to separate them. 
91. As to duration, leaves are caducous or fugacious, when they decay 
or fall very soon after expansion ; deciduous when they fall comparatively 
early or at the close of the season *, and persistent , when they last the 
whole year round or longer, as in Evergreens. 
92. The leaves of most Exogens separate from the persistent stem bv a 
joint formed at the insertion, leaving a clean scar 3 such are articulated 
with the stem ; while in most Endogens the dead leaves separate only by 
decaying away. 
93. The mode in which the leaves are packed away in the bud is named 
their Vernation or prjefoi.iation ; of which there are several ways; 
such as the conduplicate, when each leaf is infolded together lengthwise, as 
in the Beech. Magnolia, &c. 5 the plicate or plaited , when each leaf is several 
times folded (into plaits), as in the Maple, Vine, &c.; the involute, when 
the edges are rolled inwards towards the midrib, as in the Violet; the rev¬ 
olute, when they are rolled backwards, as in Azalea; the convolute , when 
the leaf is rolled up around the bud from one of its edges, as in the big; 
and the circinate, when spirally rolled up from the apex downwards, as in 
the Sundew (p. 49), and in True Ferns (p. 620). 
* * * * Stipules. 
94. The Stipules (59) often form the principal scales or coverings of 
the bud, although falling away when the leaves expand, as in the Oak 
Family, the Magnolia Family (p. 17), &c. This is perhaps the principal 
use they subserve, except when they remain, become green and foliaceous, 
and act like leaves. 
95. Leaves furnished with these appendages are said to b e stipulate; 
destitute of them they are exstipulate. Leaflets when furnished with similar 
appendages, as in the Bean (p. 95), are stipellate. 
96. Stipules are sometimes adnate or adherent to the petiole, one on 
each side, as in the Rose, Strawberry, and Clover. Sometimes they unite 
instead by their opposite margins on the other side of the branch, as in 
Plane-tree (p. 433)'; or uniting by both margins they form a sheath ( ochrea ), 
as in the Buckwheat Family (p. 385). 
