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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