66 BOTANY, 
A. DICHOTOMOUS, 
1. Forked dichotomy, in which both branches of each bifurcation are 
equally developed (Fig. 38, A). 
2. Sympodial dichotomy, in which one of the branches of each bifur- 
cation develops more than the other. 
a. Helicoid sympodial dichotomy, in which the greater develop- 
ment is always on one side (Fig. 38, 2). 
b, Scorpioid sympodial dichotomy, in which the greater develop- 
ment is alternately on one side and the other (Fig. 38, C). 
B. MONOPODIAL, 
1. Botryose monopodium, in which, as a rule, the axis continues to 
grow, and retains its ascendency over its lateral branches (Fig. 39). 
2. Cymose monopodium, in which the axis soon ceases to grow, and 
is overtopped by one or more of its lateral branches. ° 3 
a. Forked cymose monopodium, in which the lateral branches are 
all developed (Fig. 40, C). 
b. Sympodial cymose monopodium, in which some of the lateral 
branches are suppressed; this may be— 
b'. Helicoid, when the suppression is all on one side (Fig. 40, 
D); or— 
b". Scorpioid, when the suppression is alternately on one 
side and the other (Fig. 40, A and B). 
Practical Studies.—(a) Mount and examine under a low power of 
the microscope or by the naked eye alone the following in order as 
examples of thallomes: 1, Green Slime; 2, Pond Scum; 3, the first 
stage of a fern ‘‘seedling” (little flat green growths, 3-5 mm. across, 
which often appear on the earth near ferns in greenhouses); 4, Sea- 
lettuce (Ulva); 5, Irish moss (Chondrus), the latter showing a much- 
lobed form. 
* (b) Study as examples of caulome forms the following in order 
1, the stem of Lamb’s Quarters, or Indian corn; 2, runners of the 
strawberry; 3, root-stocks of blue grass; 4, tubers of the potato; 5, 
corms of Gladiolus, or Indian turnip; 6, bulb-axis of the onion; 7, 
flower-axis of anemone, buttercup, tulip, or lily; 8, tendrils of the 
grape, or Virginia creeper; 9, thorns of honey-locust, or plum. 
(c) Study as examples of phyllome forms: 1, leaf of apple, cherry, 
or Indian Corn, etc.; 2, bracts of flower-cluster of cress, sweet- 
william, golden-rod, or aster; 3, scales of buds of hickory or lilac; 
4, floral"envelopes of anemone, buttercup, tulip, or lily; 5, stamens 
of any of the above; 6, carpels of anemone, buttercup, columbine, 
etc.; 7, tendrils of pea, or vetch; 8, spines of thistles. 
