160 VARIETIES OF PARALLEL VENATION. 
the margins (figs. 312 and 313), and are connected by numerous 
branching veinlets, as in the leaves of the Beech, Spanish 
Chestnut, Holly, Oak ; or the midrib gives off branches from 
its sides, which proceed at first towards the margins, and then 
curve towards the apex, terminating finally within the margins, 
with which they are connected by small veins, as in the Dead- 
nettle (fig. 314), and Lilac. The latter modification of arrange- 
ment is sometimes termed true netted venation. 
B. Radiated or Palmately-veined.—This name is applied to a 
leaf which possesses two or more ribs that arise from at or near 
the base of the lamina, and diverge from one another towards 
its margins, and are connected by branching veins, as in the 
Melon (fig. 810) and Castor-oil plant (jig. 332). The ribbed 
venation, as seen inthe Cinnamon ( fig. 309), is but a modification 
of this variety, in which the ribs, instead of diverging from one 
another, run in a curved manner from at or near the base of the 
blade to the apex, towards which they converge, such ribs being 
connected together by branching veins. If a ribbed leaf has 
three ribs proceeding from the base, it is said to be three-ribbed 
or tricostate ; if five, five-ribbed or quinquecostate ; if more than 
five, many-ribbed or multicostate. If the midrib of such a leaf 
gives off on each side, a little above its base, another rib, it is 
said to be triple-ribbed or triplicostate, as in the common Sun- 
flower (fig. 315, b) ; or if two such ribs arise on each side of the 
midrib, it is termed quintuple-ribbed or quintuplicostate. These 
ribbed leaves have frequently a great resemblance to parallel- 
veined leaves, from which, however, they may be at once dis- 
tinguished by their ribs being connected by branching veins. 
2. Varieties of Parallel Venation. 
The term parallel-veined is not strictly applicable in all cases, 
for it frequently happens that the veins are radiated ; but from 
the difficulty of finding a name which will comprise all the 
modifications to which such leaves are liable, it must be under- 
stood that we apply the term parallel-veined to all leaves in 
which the main veins of the lamina are more or less parallel and 
only connected by unbranched parallel veinlets. 
There are certain characteristic variations of parallel vena- 
tion. Thus, the main veins may either proceed in a somewhat 
parallel direction from the base to the apex of the lamina, to 
which point they converge more or less (fig. 316), as in the 
ordinary ribbed variety of reticulated leaves already noticed, 
and are connected by simple unbranched transverse veinlets ; 
or they diverge from one another towards the circumference of 
the blade (fig. 317), as in the radiated-veined variety of reti- 
culated leaves, and are likewise united by cross-veinlets. The 
leaves of Grasses, Lilies, and the common Flag, may be taken 
