THE STUDENT'S MANUAL
(2) Phyllotaxy or the arrangement of leaves.
(a) The verticillate or cyclic arrange-
ment: two or more leaves at one node 1480.
(b) The alternate or spiral arrange-
ment: single leaf at each node 1480.
1. Angular divergence: how obtained.
(a) External: blade— expanded part
of the leaf 1041; petiole — stalk upon which the leaf grows 1461; stipules — appendages at the axil 1827.
(b) Internal: epidermis — upper and
lower surfaces of leaf 622; stomata 1831; cuticle 490; mesophyll — giving the leaf its color 1209; chloroplast 393; vein ends — penetrating among mesophyll cells 1041.
(c) Closed venation: parallel veined
leaves, as in grass and the
lily 1041. (d£) Open vena- *
tion: net- [ 1. Pinnate leaves. veined or 4
reticulate 2. Palmate leaves. jL041. l
(4) Special forms In leaf structure: 1042; bracts 255; cupule 487; palet 1411; glumes 775; scales 1686; bulb 286; spines 1799; tendril 1888; pitcher plants 1495; carnivorous plants 338.
(a) Dorslventral: exposing two surfaces to different conditions 545.
(3) Structure of the leaf.
(5) Position of leaf:
THE ROOT: that part of the plant growing downward 1632.
(b) Radial: all sides exposed alike
545.
(c) Profile: one edge turned toward
intense sunlight, as compass-plants 435.
a. Epidermis: the outside covering.
b. Cortex: more or less thickened.
c. Axis: the woody central part.
d. Root-cap: that protects the tip cells in bur-
rowing.
e. Root-hairs: to help the root in absorbing.
f. Root tubercles: which supply the plant with
nitrogen 1633.
g. Rhizoids: holdfasts and absorbing organs
1606. h. Mycorrhiza: aiding roots in absorbing 1294.
7. THE FLOWER: a modified shoot of seed-plants 685. a. Where and how the flowers grow: 925.
(1) Solitary: occurring solitary upon plants.
(2) Inflorescence: clusters of flowers.
2270
