. Elementary botany : theoretical and practical. A text-book designed primarily for students of science classes connected with the science and art department of the committee of council on education . Botany. 66 Elementary Botany overlapping is carried further (as in fig. iv.), it is said to be spiral or twisted. (U) The separate leaves bent or rolled.—When, as in the Columbine, involute leaves touch by their edges without over- lapping (v.), the vernation is induplicate. When, as in the Privet, conduplicate leaves are bent around one another (vi.), it is eq^uitant; whilst when, as in the Sage
. Elementary botany : theoretical and practical. A text-book designed primarily for students of science classes connected with the science and art department of the committee of council on education . Botany. 66 Elementary Botany overlapping is carried further (as in fig. iv.), it is said to be spiral or twisted. (U) The separate leaves bent or rolled.—When, as in the Columbine, involute leaves touch by their edges without over- lapping (v.), the vernation is induplicate. When, as in the Privet, conduplicate leaves are bent around one another (vi.), it is eq^uitant; whilst when, as in the Sage, they are only half folded over one another (vii.) they are obvolute or half equitant. When, as in the Apricot, a convolute leaf has another rolled outside it (vui.), the vernation is supervolute. In considering branch- ing, whether of root, stem, or leaf, we must carefully distinguish the main axis, foot or podium, and the branches. This, however, is not always easy. I. In some cases the main axis ceases to grow when the branches are formed. Such branching is called dichotomy or dicho- tomous branching. The podium has at its extremity two growing points, each of which develops a branch. Sometimes both of these grow equally vigorously, each bifurcating in its turn, and a true dichotomy or forked system is produced (fig. 99, a). Sometimes one branch becomes more strongly developed than the other; the system now becomes sympodial, the successive strong branches looking as though they were the continuous axis, and the weaker branches appearing to be lateral ones. If the stronger bifurcation is. Fig. 99.—Diagrams of dichotomous branching. Ai normal dichotomy, the forked branches equally developed, and becoming the podia of new dichotomies. B^ Bostrychoid dichotomy, one fork-branch only becoming the podium of a new dichotomy : in this case the left (/). C, cicinnal dichotomy; one fork branch, alternately left (/) and right (?), becoming the podium of a new dichotomy. B and C ar
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1888
