THE ARCHEGONIAT^E 



221 



mella, which in position suggests the primary vascular bundles of the Fern- 

 embryo. From the amphithecium, by a second series of periclinals, there is 

 separated on its inner side a layer of cells which forms the archesporium. 



The lower part of the embryo develops a large foot like that in the embryo of 

 the Hepaticse ; but between the foot and the upper part of the embryo there is 

 developed a zone of actively dividing cells, which cause the sporophyte to elon- 

 gate rapidly by basal growth. This growth may be limited, as in Notothylas, 

 where the sporophyte never assumes a large size ; but in some species of Antho- 

 ceros it continues for several mouths, indeed, as long as the gametophyte 

 remains active, and the slender sporophyte may reach a length of six to 

 eight centimetres. These large sporophytes have a well-developed assimila- 



FIG. 182. A-C, Anthoceros fusiformis. A, gametophyte with four sporophytes 

 attached (X2). B, upper part of full-grown sporophyte, discharging spores. 

 C, base of sporophyte surrounded by the calyptra, or sheath (X 4). D, Dendro- 

 ceros Javanicus, enlarged. (After LEITQEB.) E, Notothylas orbicularis (x4). 



tory tissue-system, several layers of the outer cells forming a spongy green 

 parenchyma which communicates with the outside by means of stomata, pre- 

 cisely like those in the leaves of the higher plants. Were the sporophyte put 

 into communication with the earth by the development of a root, it would be 

 quite independent of the gametophyte. 



The archesporium shows a more or less evident separation into 

 fertile and sterile portions, which suggest a condition something 

 like the formation of sporangia in the simplest Ferns. The sterile 

 cells in some cases develop into elaters, but these differ somewhat 

 from those of the Hepaticae. 



