Metaphyta L iliu m. 1 67 



(c, n\ the stalk becomes the funicle. The cells immedi- 

 ately beneath the nucellus multiply tangentially and form 

 the rudiments of the coverings of the ovule, the inner coat 

 first, and the outer from beneath the origin of, and subse- 

 quently to, the inner coat (D, /"/', at). The ovule, though 

 anatropai when ripe, is orthotropal at first, gradually becom- 

 ing anatropal as it increases in size. These coverings to the 

 sporangium are obviously new developments not present at 

 all in the sporangia of the lower plants. The nucellus alone 

 is the morphological spoiangium comparable to that of the 

 fern. The cell in the terminal portion of the nucellus 

 immediately beneath the epidermis divides into two an 

 upper and a lower. The former becomes the tapetum, 

 which in the ovosporangium is composed of one, or a very 

 few, cells, whilst the latter becomes the archesporium (B, m). 

 The archesporium whilst sunk in the nucellus next divides 

 into four cells, of which one only becomes an ovosoore 

 (macrospore, embryo-sac). The other three cells, which are 

 thus to be considered as barren ovospores, remain in a semi- 

 disorganised condition on the summit of the fertile ovospore. 

 This latter increases in size and very soon shows signs of 

 division. The nucleus divides into two, each daughter 

 nucleus retreating to opposite ends of the ovospore. Each 

 of the two new nuclei again subdivides into four, and round 

 three of either set protoplasm collects, thus forming three 

 cells at either end of the ovospore. The two remaining 

 nuclei reapproach the centre of the ovospore and there fuse, 

 forming a new secondary nucleus for the ovospore. We 

 have thus the contents of the ovospore subdivided into three 

 small cells at the end nearest to the tapetum, and three small 

 cells at the opposite end, with a large secondary nucleus 

 between them (fig. 88). The cells of the upper of these two 

 sets are arranged so that two cells are above and one be- 

 neath, the odd one having for its nucleus the sister of that 

 nucleus which helped to form the new secondary nucleus of 

 the ovospore. This lower cell is the ovum proper, whilst 



