BOOK II. 
GENERAL CONSIDERATIONS. 
287 
ill which tliis is in some measure departed from. In the 
common Asparagus the shoots produce a number of lateral 
buds, which all develope and influence its form, as the buds 
of dicotyledons ; so that the cylindrical figure of monocotyle- 
dons is exchanged for the conical; its internal structure is 
strictly endogenous. In Grasses a similar conical figure pre- 
vails, and for the same reason ; but they have this additional 
peculiarity, that their stem, in consequence of the great ra- 
pidity of its growth, is fistular, with transvere phragmata at 
its nodes. The phragmata are formed by the crossing of 
woody bundles from one side of a stem to the other ; and are, 
perhaps, contrivances to enable the thin cylinder of the stem 
to resist pressure from without inwards. 
In such herbaceous plants as Colchicum, the stem, after a 
time, is a small tuber with two buds ; one at the apex, which 
becomes the flowering stem and leaves ; the other at the base, 
directed downwards at an obtuse angle. Such a tuber is 
multiplied by the latter bud, which pushes forward obliquely, 
and turning upwards, throws up a new flowering stem in the 
autumn ; the base of the flowering stem thickens, enlarges, and 
assumes the appearance of a new cormus ; in the spring, leaves 
sprout forth, and elaborate matter enough to fill the cells of 
the new cormus with faecula, and to organise another oblique 
bud at the base, and then the growth of a new individual is 
accomplished. In the mean while, the original cormus is ex- 
hausted of all its organisable contents, which are consumed 
in the support of the young cormus produced from its base ; 
and, by the time that the growth of the latter is completed, 
the mother is shrivelled up, and dies. It is easy to conceive 
many modifications of this. 
Upon one or other of the two plans now explained are all 
flowering plants developed; but in flowerless plants it is dif- 
ferent. In arborescent Ferns the stem consists of a cylinder 
of hard sinuous plates, connected by parenchyma, and sur- 
rounding an axis, hollow, or filled up with solid matter. It 
would seem, in these plants, as if the stem consisted of a mere 
adhesion of the petioles of the leaves in a single row ; and that 
the stem simply lengthens at the point, without transmitting 
