ANDRCECIUM, OB STAMENS. 



255 



diagram, Fig. 503, which should, however, show the median 



partitions in the cross-section, or traces of them. Pollen is a 



special development into peculiar cells of what would 



be parenchyma in a leaf. Its formation normally 



begins in four places, which may remain separate 



up to maturity, or the two on each side of the axis 



or connective may early be confluent into one cell. 



468. Of the many deviations of the typical two- 

 celled anther, with its cells parallel and united 

 longitudinally by a connective, the simplest and 

 commonest is that in which (as in Fig. 505) the 

 two cells diverge below and remain united only at 

 their apex. Next, the two cells may, in their early 

 development, become confluent at the apex, as in the 



Mallow family (Fig. 506), so as to form a continuous pollin- 

 iferous cavity within, opening by a continuous suture round the 

 margin : here the anther is unilocular or one-celled by confluence. 

 In another way, the anthers of some species of Orthocarpus (gen- 

 erally resembling Fig. 505, but the lobes or cells quite distinct 

 or even separated at apex) lose one of the cells by partial or 

 complete non-development and so become one-celled by abor- 

 tion. The anther of Gomphrena (Fig. 507) is completely uni- 

 locular by abortion or suppression of the companion cell. Thus 

 losing one half, it is said to be dimidiate, or halved. 



469. The two anther-cells, such as those of Fig. 505, some- 

 times diverge so much that they form a straight line transverse 

 to the filament, as in Monarda (Fig. 



508), in which their contiguous ends 

 so coalesce as to give the appearance 

 of a one-celled anther fixed by the 

 middle. Or, again, the two cells may 

 be separated by the enlargement of 

 the connective between them, as in Cal- 

 amintha, Fig. 509. This enlargement 

 is extreme in the great genus Salvia, in 

 which a very long and narrow connec- 

 tive gives the appearance of a filament astride the apex of the 



FIG. 603. Diagram to illustrate the morphology of the stamen, on the idea that the 

 anther answers to leaf-blade: the lower portion being filament and a part of the anther, 

 in section, the upper a part of a leaf. 



FIG. 504. Stamen of Menispermum Canadense, the quadrilocellate anther divided. 



FIG. 605. Stamen of Pentstemon pubescens, with anther-cells divergent. 



FIG. 506. Stamen of Mallow (one of the cluster of Fig. 485), the two cells and utures 

 confluent into one. 



FIG. 507. Anther of Gomphrena or Globe Amaranth, mediated, of a single cell, 

 dehiscent. 



