. 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. PHYLLOTAXY, OH LEAF ARRANGEMENT. 49 231. The alder cycle. In tho alder, birch, sedges, &c, the ejele fas not com- plete until the fourth leaf is roached. The fourth leaf stands over the first, the fifth over the second, &o, forming three vertical rows. Here call the cycle -J-; 1 denote the turns, 3 the leaves, and this fractiou itself the angular distance (J- of 360°). 232. The cherry cycle, la tho cherry, apple, peac
. 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. PHYLLOTAXY, OH LEAF ARRANGEMENT. 49 231. The alder cycle. In tho alder, birch, sedges, &c, the ejele fas not com- plete until the fourth leaf is roached. The fourth leaf stands over the first, the fifth over the second, &o, forming three vertical rows. Here call the cycle -J-; 1 denote the turns, 3 the leaves, and this fractiou itself the angular distance (J- of 360°). 232. The cherry cycle, la tho 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. The sixth leaf is over tho first, the seventh over the second, &c., forming five vertical rows. Coll this the 2 cycle; 2 denotes tho turns, 5 the leaves in the cycle, and the fraction itself the an- gular distance (f of 360°). 233. The Osage-orange CYCLE. In tho common hedge plant, Osage-orange, the holly, evening primrose, flax, etc., we find no leaf exactly over the first until we come to the 9th, and in reaching it the spiral makes three turn?. Here the leaves form eight vortical rows. It te a $ cycle ; 3 the number of turns, 8 the number of loaves, and the fraction the angular distance between the leaves ($â of 360°). 234. The cycles compared. These several fractions which represent the above cycles form a series as follows: ^, $, f, f, in which each term is the sum of the two preceding. The fifth terms in order will, therefore, ; and this arrangement ia actually realized in. 96, Phyllotaxy of the cone (cyclo ^*) of Pinus serotinu. 97, cherry cycle Cj), ns seen from â¢bove, forming necessarily that kind of aestivation called quincuntial. 235. The white pine cycle. -In the young shoots of the white pine, in conos of most pines, in flea-bane (Erigeron Canadonse), etc., the fourteenth leaf
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