THE ESSENTIAL ORGANS STAMENS. 121 



filament appears to arise on the face of a scale-like body, and in 

 Simaba and Larrea it stands at the back of an analogous scale. 



The scale-like organs situated at the base of filaments, or connected 

 with fascicles of stamens (Tiliacece), are by some regarded as furnishing 

 evidence for the doctrine of chorisisj but they are more probably merely 

 barren lobes of compound stamens. 



The Anther its parts. The anther has a typical form, which is 

 subject to very great modification in different cases. It corresponds 

 to the microsporangium of some of the higher Cryptogams. A regular 

 anther (fig. 223, 6) is an oblong body, divided perpendicularly into 

 two lobes ; the division is usually marked by a furrow on the face, 

 and a ridge on the back (or dorsum). The central region, which is 

 solid and represents the midrib of a leaf, is called the connective ; 

 the lobes are hollow dilatations of the lamina, and contain the 

 pollen. At each border, usually rather toward the face, is often to 

 be seen a vertical line, called the suture, indicating the place where 

 one class of anthers split open to discharge the pollen. 



Attachment to the Filament. The anther is attached to the 

 filament in several ways : if the filament runs directly without 

 interruption into the base of the connective, like the stalk of an 

 ordinary leaf, it is said to be innate or basifixed ; if the filament 

 runs up the back of the anther as it were, so that the latter is 

 more or less free at the base, the anther is adnate or dorsifixed ; 

 if the filament is attached by a slender apex to about the middle 

 of the back of the anther, the latter is versatile. In some cases 

 the anther is pendulous from the apex ; it is then sometimes called 

 apwifixed. In the Tulip, the capillary point of the filament runs 

 up into a conical pit in the base of the connective. 



Modifications. The modifications of the anther result from various 

 causes from development of the connective, from the presence of ap- 

 pendages, from variation of form of the anther-lobes, and from special 

 conditions of the internal cells ; and there are also important differences 

 in the manner of bursting, or dehiscence, for the discharge of the pollen. 



The Connective. The connective is normally a solid rib, running 

 up the middle of the anther. If the lobes of the anther extend 

 upward or downward beyond it, the summit or base of the anther 

 (or both) becomes emarginate. On the other hand, the summit of 

 the connective is prolonged in a membranous form in Viola, and 

 also in the Composite. In Paris (fig. 226) the apex is lengthened 

 into a point, also in Asarum, Magnolia, &c. ; in Xylopia into a 

 fleshy mass ; in the Oleanders into a feathered process, &c. In 

 two of the stamens of Viola the base of the connective has petaloid 

 spur-like appendages ; and still more remarkable states occur in 

 the Melastomaceae. 



