THE LEAF 65 
Bracts are leaves in the axils of which floral shoots 
are produced. They are usually green, but may be red 
or otherwise coloured or colourless, They resemble 
scale leaves in form and origin. 
Floral Leaves.—The flowers produced by Angiosperms 
are formed of structures which have the same morpho- 
logical value as foliage leaves. They are called FLORAL 
LEAVES. In a typical flower there are four series of 
floral leaves, the sepals, petals, stamens, and carpels. 
The sepals are usually green, and resemble bracts. The 
petalsare of a more delicate structure, and are variously 
coloured. Stamens are generally filamentous in shape, 
and produce pollen in special receptacles. The carpels 
may be regarded as scale leaves which have closed 
together, producing receptacles in which ovules are 
borne. 
35. The Arrangement of Leaves.—Leaves are ar- 
ranged on the stem in a characteristic regular manner. 
The manner in which leaves are arranged on a stem is 
spoken of as PaynnoTaxy. There are two kinds of phyl- 
lotaxy: (a) spiral, (6) cyclic. In spiral phyllotaxy the 
bases of the leaves are arranged round the stem in the 
form of a spiral, one leaf being produced at each node. 
In cyclic phyllotaxy two or more leaves forming a whorl 
are produced at each node. If two leaves are produced 
at each whorl the leaves are Opposite, if more than 
two, VERTICILLATE (fig. 41 a). If the pair of leaves at 
one node are placed at right angles to the pair of leaves 
below we have the DEcussATE arrangement (fig. 40) with 
four rows of leaves on the stem, e.g. Salvia. In spiral 
phyllotaxy the leaves are said to be ALTERNATE. If we 
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