SPECIAL MORPHOLOGY: LIVERWORTS. 



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130 



antheridia in their axils, and are then combined together as a catkin 

 (amentum). In flat-stemmed Liverworts, the antheridia are always 

 imbedded in a cavity in the substance of the stem, opening out- 

 ward. In many we find them very much scattered upon the 

 surface (Pellia epiphylla)\ in others a definite part of the stem, 

 rising in a disc-like form, bears the antheridia (Fegatella conica) ; in 

 others, again, this disc rises shield-like upon a pedicle, and is then 

 frequently notched, lobed, &c., at the margin, as, for instance, in 

 Marchantia polymorpha. 



As I purpose saying what is necessary of the signification of these 

 antheridia under the head of Mosses, I will here 

 pass the subject by, merely giving Fegatella co- 

 nica as an illustration (fig. 130.). I must, how- 

 ever, be permitted to remark that here, also, hasty 

 observations have led to remarkable misconceptions. 

 Almost all manuals speak of flask-shaped anthe- 

 ridia extending upwards into a long neck : none 

 such, however, are to be met with. In Marchantia 

 polymorpha and others, the cavity has a flask-like 

 form, enclosing the antheridia below, but open as 

 a narrow canal at the top, which sometimes rises 

 cup-shaped above the surface of the stem, as in 

 Anthoceros, as a papilla, in Pellia epiphylla, or as 

 a pedicle, in Riccia. Within, this cavity is in- 

 vested with a dense epidermis. On a superficial 

 examination the flask-like outline of this epider- 

 mis has been mistaken for the antheridium, which 

 is entirely separated from that membrane, lies 

 under the canal, and is always rounded off at 

 the end in an upward direction. In like manner 

 the so-called cuspides in Riccia do not belong to 

 the antheridia, but to the elevation of the paren- 

 chyma at the margin of the cavity enclosing these 

 antheridia. 



99. The roundish stem of the Liverworts has a wholly si- 

 milar composition to that of Mosses. The leaves, on the other hand, 

 consist, without exception probably, of merely one simple cellular 

 layer. The flat stem presents many varieties, consisting frequently 

 of one simple layer of thin-walled cells, or it exhibits in its axis the 

 elements of the ordinary stem. The parenchyma around this is 

 formed of one or many cell-layers, often covered on the surface 

 with a perfect epidermis, containing stomata of a peculiar kind, 

 namely, wart-like, elevated cellular masses, perforated at the point 

 by an intercellular passage, which leads into a cavity invested with 

 lax and often flask-shaped cells. In Fegatella and Marchantia the 

 cells of the central mass of the stem have beautifully porous or 



180 Fegatella conica. A, A portion of the little plant, with two disc-like elevations 

 of the stem (a, a), in which the antheridia are imbedded. B, A part of a section of 

 one of these elevations. The hollowing in is of a flask-like form, furnished with a 

 tough epidermis. The antheridium consists internally of a cellular sac, filled by 

 one large cell. 



