. Class-book of botany : being outlines of the structure, physiology and classification of plants : with a flora of the United States and Canada . Botany; Botany; Botany. PHTLLOTAXY, OR LEAF ARRANGEMENT. 49 231. The alder cycle. In the alder, birch, sedges, &o., the cjcle is not com- I plete until the fourth leaf is reached. The fourth leaf stands over the first, the fifth .over the second, &c., forming three vertical rows. Here call the cycle -J-; 1 denotes the turns, 3 the leaves, and this fraction itself the angular distance (^ of 360°). 232. The cheery cycle. In tlie cherry, apple,
. Class-book of botany : being outlines of the structure, physiology and classification of plants : with a flora of the United States and Canada . Botany; Botany; Botany. PHTLLOTAXY, OR LEAF ARRANGEMENT. 49 231. The alder cycle. In the alder, birch, sedges, &o., the cjcle is not com- I plete until the fourth leaf is reached. The fourth leaf stands over the first, the fifth .over the second, &c., forming three vertical rows. Here call the cycle -J-; 1 denotes the turns, 3 the leaves, and this fraction itself the angular distance (^ of 360°). 232. The cheery cycle. In tlie cherry, apple, peach, oak, willow, etc., neither the third nor the fourth leaf] but the sixth, stands over the first; and in order to reach it the thread makes two turns around the stem. Tlje sixth leaf is over the first, the seventh over the second, &c., forming five vertical rows. Call this the § cycle; 2 denotes the turns, 5 the leaves in the cycle, and the fraction itself the an- gular distance (| of 350°). 233. TiiB OsAGE-ORANGB CYCLE. In the common hedge plant, Osage-orange, the holly, evening primrose, flax, etc., we find no leaf exactly over the first untU we come to the 9th, and in reaching it the spiral makes three turns. Here the leaves form eight vertical rows. It is a f cycle ; 3 the number of turns, 8 the number of leaves, and the fraction the angular distance between the leaVes (f of 360°). 234. The cycles compared. These several fractions which represent the above cycles form a series as follows: J, fc |, f, in which each term is the sum of the two preceding. The fifth terms in order will, therefore, be Ji ; and this arrangement i3 actually realized in. 96, Phyllotaxy of the cone (cycle -j'-j) of Pinus serotina. 97, cherry cycle (|), as seen from above, forming necessarily that kind uf sestivation called quincuiitial. 235. The white pine cycle. In the young shoots of the white pine, in cones of most pines, in flea-bane (Erigeron Oanadense), etc., the fourteenth leaf s
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