XVU1 INTRODUCTION. 



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diadelphous, when so united into two clusters. The term is more especially ap- 

 plied to certain Leguminosce, in which nine stamens are united in a tube slit open on 

 the upper side, and a tenth, placed in the slit, is free. In some other plants the sta- 

 mens are equally distributed in the two clusters. 



triadelphous, pentadelphous, polyadelphous, when so united into three, five, or 

 many clusters. 



syngenesious, when united by their anthers in a ring round the pistil, the filaments 

 usually remaining free. 



didynamous, when (usually in a bilabiate flower) there are four stamens in two 

 pairs, those of one pair longer than those of the other. 



tetradynamous, when (in Cruciferce) there are six, four of them longer than the 

 two others. 



exserted, when longer than the corolla, or even when longer than its tube, if the 

 limb be very spreading. 



114. An Anther (109) is 



adnate, when continuous with the filament, the anther-cells appearing to lie their 

 whole length along the upper part of the filament. 



innate, when firmly attached by their base to the filament. This is an adnate 

 anther when rather more distinct from the filament. 



versatile, when attached by their back to the very point of the filament, so as to 

 swing loosely. 



115. Anther-cells may be parallel or diverging at a less or greater angle ; or diva- 

 ricate, when placed end to end so as to form one straight line. The end of each an- 

 ther-cell placed nearest to the other cell is generally called its apex or summit, and 

 the other end its base (36) ; but some botanists reverse the sense of these terms. 



116. Anthers have often, on their connectivum or cells, appendages termed bristles 

 (setse), spurs, crests, points, glands, etc., according to their appearance. 



117. Anthers have occasionally only one cell : this may take place either by the disap- 

 pearance of the partition between two closely contiguous cells, when these cells are said 

 to be confluent ; or by the abortion or total deficiency of one of the cells, when the 

 anther is said to be dimidiate. 



118. Anthers will open or dehisce to let out the pollen, like capsules, in valves, pores, 

 or slits. Their dehiscence is introrse, when the opening faces the pistil; extrorse, when 

 towards the circumference of the flower. 



119. Pollen (109) is not always in the form of dust. It is sometimes collected in each 

 cell into one or two little wax -like masses. Special terms used in describing these masses 

 or other modifications of the pollen will be explained under the Orders where they occur. 



§ 11. The Pistil. 



120. The carpels (91) of the Pistil, although they may occasionally assume, rather 

 more than stamens, the appearance and colour of leaves, are still more different in 

 shape and structure. They are usually sessile ; if stalked, their stalk is called a podo- 

 carp. This stalk, upon which each separate carpel is supported above the receptacle, 

 must not be confounded with the gynobasis (143), upon which the whole pistil is 

 sometimes raised. 



121. Each carpel consists of three parts : 



1. the Ovary^ or enlarged base, which includes one or more cavities or cells, con- 

 taining one or more small bodies called ovules. These are the earliest condition of the 

 future seeds. 



2. the Style, proceeding from the summit of the ovary, and supporting — 



3. the Stigma, which is sometimes a point (or punctiform stigma) or small head 

 (a capitate stigma) at the top of the style or ovary, sometimes a portion of its surface 

 more or less lateral and variously shaped, distinguished by a looser texture, and covered 

 with minute protuberances called papilla. 



122. The style is often wanting, and the stigma is then sessile on the ovary, but in 

 the perfect pistil there is always at least one ovule in the ovary, and some portion of 

 stigmatic surface. Without these the pistil is imperfect, and said to be barren (not 

 setting seed), abortive, or rudimentary (84), according to the degree of imperfection. 



