THE STEM. 
37 
ing the down (c), is the stipe. At Fig. 29 is a mushroom 
with the cap {d) elevated on its stipe (e). 
42. Branches spring from lateral or axillary huds. The axil- 
lary bud is at first a minute point of cellular tissue on the sur 
face of the wood, at the end of one of the lines that form the 
medullary rays (called silver grain). As it grows, the bud 
pushes through the bark, and appears as a rudimentary axis, 
which in time becomes a hranch. Other buds are formed in 
like manner, and develop themselves from the branch at first 
formed, and so on through the whole system of the plant, as in 
a large tree. The smaller branches are called twigs^ houghs^ or 
hrancMets. The branch may be considered as a tree, implanted 
upon another tree of the same species. Branches sometimes 
grow without any apparent order, the symmetrical arrange- 
ment of nature having been interrupted by disturbing causes ; 
sometimes they are opposite ^ sometimes alternate j and some- 
times, as in the pine, they form a series of rings around the 
trunk. Some branches are erect^ as in the poplar, others pen- 
dent^ as in the willow, and some, as in the oak, form nearly a 
right angle with the trunk. These various circumstances con 
stitute distinctive characters in plants, a knowledge 
of which is very necessary to the painter. Of all our 
forest trees, perhaps none, in the disposition of its 
branches, presents a more beautiful and graceful as- 
pect than the elm. The branches of trees, as they 
grow older, usually form a more open angle with the 
trunk than at first. 
43. Of stems bearing hidUets in the axis of their 
leaves, the Lilium lulbiferum^ or tiger-lily (Fig. 30), 
is a good example. These little bulbs are of a red-brown 
color, about the size of a large gooseberry. They begin soon 
after they are formed to detach themselves from the plant, and 
falling upon the ground shoot out fibers, and take root. This 
splendid fiower may thus be rapidly increased. Subterranean 
stems, or those which grow under ground, are often called 
roots, but are distinguished by their producing leaf-buds at in- 
tervals. The term rliizoma is applied to stems creeping hori- 
zontally, being partially covered by the soil, sending out roots 
from its lower, and leaf-buds from its upper side, as in the Iris, 
some of the lily roots, and in some of the orchis plants (see 
Fig. 19, a)^ the Solomon's seal (Fig. 22, A), and the Ixia (Fig. 
22, B). 
A soboles is a creeping, underground stem, sending roots 
from one part, and leaves from another. It is often called a 
42. Branches — Branchlets — Various appearances of bran^lies — Branches alter in their angies aa 'hey 
grow older. — 43, Bulb-bearing stems — Rooting sterna. 
