INTRODUCTION. XVU 



infundibuliforrn or funnel-shaped, when the tube is cylindrical at the base, but en- 

 larged at the top into a more or less campanulate limb, of wliich the lob^s often spread 

 horizontally. In this case the campanulate part, up to the commencement of the 

 lobes, is sometimes considered as a portion of the tube, sometimes as a portion of the 

 limb, and by some botanists again described as independent of either, under the name 

 of throat {fauces). Generally speaking, however, in campanulate, infundibuliforrn, 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, ac- 

 cording 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 Orchidea 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 strongly 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 projection, 

 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. 



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 ap- 

 plicable to those of individual petals ; but the flat expanded portion of a petal, cor- 

 responding to the blade of the leaf, is called its lamina, and the stalk, corresponding 

 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, consisting 

 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. 



110. 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 unsymmetrical 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 

 orms a tube round the pistil, or, if the pistil is wanting, occupies tho centre of tho 

 ower. 



