ELEMENTARY BOTANY. 
XV 
under the name of throat {fauces). Generally speaking, however, in campanulate, 
infundibuliform, or other corollas, where the lower entire part passes gradually into 
the upper divided and more spreading part, the distinction between the tube and 
the limb is drawn either at the point where the lobes separate, or at the part where 
the corolla first expands, according to which is the most marked. 
105. Irregular corollas have received various names according to the more familiar 
forms they have been compared to. Some of the most important are the 
bilabiate, or two-lipped corolla, when, in a four- or five-lobed corolla, the two or 
three upper lobes stand obviously apart, like an upper lip, from the two or three 
lower ones or under lip. In Orchidece and some other families the name of lip, or 
labellum , is given to one of the divisions or lobes of the perianth. 
personate , when two-lipped, and the orifice of the tube closed by a projection 
from the base of the upper or lower lip, called a palate. 
ringent , when very widely two-lipped, and the orifice of the tube very open. 
spurred , when the tube or the lower part of a petal has a conical hollow pro- 
jection, compared to the spur of a cock; saccate, when the spur is short and round 
like a little bag ; gibbous, when projecting at any part into a slight swelling ; faveo- 
late, when marked in any part with a slight glandular or thickened cavity. 
resupinate or reversed, when a lip, spur, etc., which in allied species is usually 
lowest, lies uppermost, and vice versd. 
106. The above terms are mostly applied to the forms of monopetalous corollas, 
but several are also applicable to those of polypetalous ones. Terms descriptive of 
the special forms of corolla in certain Natural Orders will be explained under those 
Orders respectively. 
107. Most of the terms used for describing the forms of leaves (39, 45) are also 
applicable to those of individual petals ; but the flat expanded portion of a petal, 
corresponding to the blade of the leaf, is called its lamina, and the stalk correspond- 
ing to the petiole, its claw {unguis). The stalked petal is said to be unguiculate. 
§ 10. The Stamens. 
108. Although in a few cases the outer stamens may gradually pass into petals, 
yet, in general, Stamens are very different in shape and aspect from leaves, sepals 
or petals. It is only in a theoretical point of view (not the less important in the 
study of the physiological economy of the plant) that they can be called altered leaves. 
109. This usual form is a stalk, called the filament , bearing at the top an anther 
divided into two pouches or cells. These anther-cells are filled with pollen , con- 
sisting of minute grains, usually forming a yellow dust, which, when the flower 
expands, is scattered from an opening in each cell. When the two cells are not closely 
contiguous, the portion of the anther that unites them is called the connectivum. 
1 1 0. The filament is often wanting, and the anther sessile, yet still the stamen is 
perfect ; but if the anther, which is the essential part of the stamen, is wanting, 
or does not contain pollen, the stamen is imperfect, and is then said to be barren or 
sterile (without pollen), abortive or rudimentary (84), according to the degree to 
which the imperfection is carried. Imperfect stamens are often called staminodia. 
111. In unsvmmetrical flowers, the stamens of each whorl are sometimes reduced 
in number below that of the petals, even to a single one, and in several Natural 
Orders they are multiplied indefinitely. 
112. The terms monandrous and polyandrous are restricted to flowers which have 
really but one stamen, or an indefinite number respectively. Where several stamens 
are united into one, the flower is said to be synandrous. 
113. Stamens are 
monadelphous, when united by their filaments into one cluster. This cluster 
either forms a tube round the pistil, or, if the pistil is wanting, occupies the centre 
of the flower. 
diadelphous, when so united into two clusters or phalanges. The term is more 
especially applied to certain Leguminosw , in which nine stamens are united in a tube 
slit open on the upper side, and a tenth, placed in a slit, is free. In some other 
plants the stamens are equally distributed in the two clusters. 
