354 MORPHOLOGY. 



most frequently, two simple perpendicular rows of cells are very early 

 distinguishable in each theca, from which the pollen is developed. The 

 remaining cellular tissue of the anther may be divided into three groups : 

 1. That forming the connective and the septa between the fore and 

 hinder loculi ; 2. That forming the outer walls of the cellular tissue 

 forming the thecae ; and 3., That lining the thecse, subsequently ab- 

 sorbed, and mostly elongated in a radial direction. Of these different 

 cellular tissues, only the two last portions (2. and 3.) progress in deve- 

 lopment by independent cell formation, after the staminal leaf is put 

 forth from the axis. The cellular tissue of the connective once existing 

 in its rudiments does not multiply its cells, but only expands those which 

 are already present, and changes them in manifold ways. The distri- 

 bution of the cells originally formed in the anther among these three 

 groups exhibits great varieties. Sometimes the largest portion of the 

 original or fundamental cells (as occurs in Berberis vulgaris], and some- 

 times the smallest portion of them (as in Trop&olvm minus\ are employed 

 in the formation of the connective. In consequence of such arrange- 

 ment, the thecse exhibit varieties of form, either appearing as four 

 cylindrical cavities (as in Tropceolum minus and Sparganium simplex}, 

 or as four scarcely concave, very shallow cavities (as in Berberis} ; or, 

 as is very frequent, as cavities somewhat deeper, but strongly inclined 

 together at the sides. In the last case, the septum often enters, as a 

 ridge, very deeply into the cavity ; as is seen in Canna and many other 

 of the Scitaminece ; for instance, Cosfus and Calathea, in almost all the 

 Solanacece, &c. ; and, in less striking degree, in Ctrbcra Thevetia ; and, 

 inconsiderably, in Gentiana lutea. 



The common supposition, that these projecting ridges are the ru- 

 diments of new septa, involves the false presupposition that the septa 

 in general grow from the connective out into the loculi ; but. in fact, 

 they exist earlier than the loculi, and are merely the remnants of the 

 parenchyma which has not been converted into pollen. The common 

 statement, that the thecae have grown to the connective, arises from an 

 equally false perception of the natural condition. In the transitory 

 cellular tissue of the third group, the newly arising cells are both radially 

 and tangentially arranged ; in the cellular tissue of the walls, on the 

 contrary, of the second group, they are only tangental ; by which means 

 the walls expand towards the surface, and the thecae enlarge, and con- 

 tinually acquire greater capacity, as the gradual development of the 

 pollen demands. Hence it happens, also, that the little furrow which in 

 the rudiment of the anther is actually the edge of the leaf, at a later 

 period forms the bottom of a deeper furrow, since, as the edge of the 

 septum, it cannot follow that expansion. 



Towards the time of the completion of the development of the anther, 

 a part of the cellular tissue of those plants flowering above water is con- 

 verted into spiral-fibrous or porous cells (see fig. 206. d) ; which cells, or 

 how many, are thus converted, is matter of the greatest variety. Some- 

 times the change only occurs in the epidermis alone remaining of the 

 outer walls, as in Lupinus ; more commonly, however, this remains 

 unchanged, and one (e. g. Composited) or more (many Liliacecc) layers of 

 the outer walls beneath the epidermis become spiral-fibrous cells, usually 



The five lobes of the apex of the corolla are applied together by their edges, surround- 

 ing five stamens which alternate with them, the transversely-cut anthers of which are 

 only in contact by the posterior loculus of each side, which adhere together. Within 

 are exhibited the two arms of the style in cross-section. 



