1914] MCCORMICK— SYMPHYOGYNA ASPERA 407 



to the apical cell (fig. 18), and in this particular thallus the initial 

 shown is the only one of the group which had made its appearance. 

 Moreover, a cell which would have been actively involved in the 

 development of the involucre is in the second row to the left of the 

 initial. Since similarly shaped cells may be distinguished in several 

 sections, it seems probable that the involucre has its origin from a 

 row of meristematic cells. As the archegonia (figs. 19-25) develop, 

 the thallus below them becomes meristematic, so that the archegonia 

 come to be arranged on a pad, as is common among the anacrogy- 

 nous Jungermanniales. 



The earliest stage of an archegonium might readily be mistaken 

 for a young mucilage hair; but a mucilage hair may be distinguished 

 by the bend which it makes very early toward the apical cell. By 

 transverse divisions the archegonial initial is divided into a tier of 

 three cells, and the outermost cell by three longitudinal walls is 

 divided, in the usual way, into four cells, an inner cell surrounded 

 by three outer cells (fig. 21). The neck of the archegonium is long, 

 and the neck cells are spirally arranged, as in the mosses (fig. 6). 

 There were counted 13 neck canal cells in one archegonium, and in 

 another archegonium the neck canal row was in part double (fig. 28) . 

 The egg is small, and in that respect it resembles the egg of mosses. 

 An undoubted case of fertilization was not seen, though fig. 27 

 represents an archegonium which may be interpreted as showing 

 fertilization. The withered neck cells and the presence of young 

 embryos in the same cluster add weight to this interpretation. 



ANTHERIDIA 



masses on the midrib 



on the dorsal side of the thallus, and each antheridium is surrounded 

 by a small involucre somewhat similar to the one which sur- 

 rounds each group of archegonia. (Spruce 32, pi. 30), in a dia- 

 grammatic way, illustrates the antheridial scales of 5. trivittata. 



mav 



indicating a cessation followed by 



duction of antheridia. This feature Leitgeb observed in the 



species which he investigated (26, p. 74). No plants bearing 



ma 



