THE STEM. 



37 



ing the down (c), is the stipe. At Fig. 29 is a mushroom 

 with the cap (d) elevated on its stipe (6^). 



42. Branches spring from lateral or auxiliary 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 

 m,ed\dlary rays (called silver grain). As it grows, the bud 

 pushes through the bark, and appears as a rudimentary axis, 

 which in time becomes a branch. 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 

 Iranchlets. 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; 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 penr 

 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 

 trimk than at first. 



43. Of stems bearing hulblets in the axis of their 

 leaves, the Lilium hiilMferum^ or tiger4ily (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 flower may thus be rapidly increased. Siibterranean 

 stems, or those which grow under ground, are often called 

 roots, but are distinguished by their producing leaf-buds at in- 

 tervals. The term rhizoma 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 (Fio\ 22, A), and the Ixia (Fig. 

 22tB). ^ V ^ , ;, 



A sololes 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 branches — Branches alterintheirang.es as tbey 

 jrow older. — 43. Bulb-bearing stems — Rooting stems. 



