| 释义 |
‖ phyllotaxis Bot.|fɪləʊˈtæksɪs|
[mod.L., f. Gr. ϕύλλο-ν leaf + τάξις arrangement.]
The arrangement or order of leaves (or other lateral members, e.g. scales of a pine-cone, florets of a composite flower, etc.) upon an axis or stem; the geometrical principles of such arrangement. Also ˈphyllotaxy.
The principal kinds of phyllotaxis are (1) the cyclical or verticillate, in which a number of leaves (two or more) stand at the same level, forming a pair or whorl; and (2) the spiral or alternate, in which each leaf stands singly, their points of insertion forming a spiral (the genetic spiral) round the stem; in the latter case the phyllotaxis is expressed by a fraction denoting the angle (or portion of one turn of the spiral) between two successive leaves; thus in a 2/5 phyllotaxis there are 5 leaves in every 2 turns of the spiral.
1857Henfrey Elem. Bot. §60 A particular study of those laws has been pursued, under the name of Phyllotaxy. 1863Darwin in Life & Lett. (1887) III. 51 Do you remember telling me that I ought to study Phyllotaxy? 1875Bennett & Dyer Sachs' Bot. 173 In a 2/5 phyllotaxis..the 6th member stands over the 1st, the 7th over the 2nd, and so on.
Hence phylloˈtactic, phylloˈtactical adjs., belonging or relating to phyllotaxis.
1857Henfrey Elem. Bot. §140 [In the Flower] the leaves, arranged according to the general phyllotactic laws, are more or less changed in form and texture. 1888Henslow Orig. Floral Struct. xxxii. 339 From phyllotactical reasons, it is clear that the origin and arrangements of the floral members are entirely foliar. |