210 



ORIGIN AM) RELATIONSHIPS of nil I I M'oK WGIATAE 



I lu large, green sporophyte, however (fig, 190, A, .«/>), never attains complete inde- 

 pendence, as no proper root is developed and it is dependent for its water supply 

 upon tin gametophyte. 



In all of the Eusporangiates, the- embryo is much latei in developing its organs 

 than in tin- Leptosporangiates, and thus resembles the Bryophytes; moreover, the 

 embryo reaches a very much larger size before it attains its independence. Even 

 after the young sporophyte has developed several roots and leaves, it may still 



Fig. 110. 



A. Gametophyte of Anthoctroi sp. with the large 



porophyte, sp, attached to it. Uppei part 



.-lit into v. lives which allow 



the escape of spores. 



B, C. Two gametophytes of Marattia ilouglasit. with 



attached sporophyte. Sporophyte emerges 



upon upper side of gametophyte, very much 



as in Jnthoceros, but a root, r, is developed 



which penetrates lower side of gametophyte 



and connects the young sporophyte with the 



earth. g, gametophyte; sp, sporophyte; 



/, first leaf; r, primary root. 



maintain its connection with the gametophyte and he to a certain extent dependent 

 upon it in a way which forcibly recalls the relation of gametophyte and sporophyte 

 in the mosses. This condition, which furnishes a very strong argument in favor of 

 the primitive nature of the Eusporangiates when compared with the Leptosporan- 

 giates, is especially pronounced among the Ophioglossaceae, where it may even go so 

 far that spores are developed before the connection of gametophyte and sporophyte 

 is finally sundered. 



In the true mosses the sporophyte is exceedingly specialized and shows but a 

 very remote resemblance to that of the Ptei idophytes. In Anthoccros, however, the 



Fig. 



91. 



Diagrams which show the similarity in form of the very 

 youni: sporophyte in hithocrros, A, and Ophioplossum , 

 B. In the former the upper portion becomes an elong- 

 ated capsule within which spores are produced. The 

 shaded portion shows layer of sporogenous tissue sur- 

 rounding central sterile tissue or columella. The 

 zone, m, between capsule and foot, /, is composed of 

 mcristematic tissue. In Ophio^lossutn the upper part 

 of the young sporophyte forms the primary leaf, or 

 rledon, cor, which is not sporogenous. The colum- 

 ella of Jnthoceros is replaced by the axial vascular 

 bundle, v.b. At the junction of the cotyledon and 

 foot arises the primary root, r, which finally penetrate! 

 the foot and enters the ground. 



most highly developed of the horned liverworts, then are a number of very significant 

 structural details that are very strongly reminiscent of the young sporophyte ol 

 Ophi'jglossum moluccanum. In both of these forms tin young embryo has a very 

 large toot and a conical upper region 1 tig. [91). This upper portion in Ophioglossum 

 develops into the cotyledon; in Anth . into tin spore-bearing part of the sporo- 



phyte. Above the toot in Anthoceros there is developed a zone of meristematic 

 tissue by means of which new cells are added to the base of the growing sporo- 



