66 BOTANY. 



A. DICHOTOMOITS. 



1. Forked dieliotomy, in which both branches of each bifurcation are 

 equally developed (Fig. 38, A). 



2. Sympodial dieliotomy, in which one of the branches of each bifur- 

 cation develops more than the other. 



a. Selicoid sympodial dieliotomy, in which the greater develop- 

 ment is always on one side (Fig. 38, E). 



6. Scorpioid gympodial 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). 



3. Cymose monopodium, in which the axis soon ceases to grow, and 

 is overtopped by one or more of its lateral brandies. 



a. Forked eymose monopodium, in which the lateral branches are 



all developed (Fig. 40, C). 

 h. Sympodial eymose monopodium, in which some of the lateral 

 branches are suppresse4; this may be — 

 b'. Helicoid, when the suppression is all on one side (Pig. 40, 



D); or— 

 6". 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 (he earth near ferns in greenhouses); 4, Sea- 

 lettuce (Ulva); 5, Irish moss (Chondrus), the latter showing amuch- 

 lobed form. 



(J) Study as examples of caulome forms the following in order 

 1, the stem of Lamb's Quarters, or Indian corn; 3, 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 pliyllome forms: 1, leaf of apple, cherry, 

 or Indian Corn, etc.; 3, 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. 



