Poly gala polygama and P. paiiciflora. 135 



Nectary. — C. In the subterranean cleistogamic flower no 

 certain indication of a nectary- has been found. 



Seeds. — The evident flowers, as already stated, commonly 

 fail to bring forth seeds. When seeds are produced no dif- 

 ference has been observed in those resulting from the differ- 

 ent types of flowers. 



The development of the seed-wall presents some points of 

 interest. The individual coats, at the time when they arise as 

 folds growing up over the nucellus, consist over nearly their 

 whole extent of two cell-layers. The inner (secundine) under- 

 goes relatively little development and in the mature state is 

 hard to find. The cells of the outer coat enlarge, and from 

 the first are sharply marked off from the surrounding tissue. 

 At the time of pollination the primine is a two-layered envel- 

 ope, whose cells are rich in protoplasm and have strongly 

 marked nuclei. Anticlinal cell division takes place rapidly 

 at this time. The cells of the secundine at flowering time are 

 somewhat vacuolated and have small nuclei. From then 

 onward they gradually become larger, vacuolated and degen- 

 erate, and may be found only as a thin, imperfect layer lining 

 the hard testa of the ripe seed. 



The cells of the primine retain their almost meristematic 

 character, dividing anticlinally, so that although the ovule is 

 swelling rapidly, their axes remain equal. As the corolla 

 withers the tw^o layers composing the primine coat become 

 differentiated : the outer ceases to divide and its cells to 

 enlarge. The inner undergoes still more active anticlinal 

 division than at first so that it becomes a layer of columnar 

 cells perpendicular to the surface. The outer layer begins to 

 develop epidermal processes which in time become the hairy 

 covering. As the ovule approaches its full size the inner 

 columnar cells cease dividing and elongate rapidly till they 

 may fairly be described as needle shaped. Their walls now 

 become greatly indurated, and thus arises the hard coat of the 



