128 



THE MARATTIALES 



Hum and its general behavior are so much like the form which occurs in Ophio- 

 glossum as to leave little room for doubt that the two forms are either identical or 

 very closely related. The conidia (fig. 96, /), while occurring in the Marattiaceae, 

 are perhaps less frequent, but in form and structure are much like those of the 

 endophyte of Botrychium. The most noticeable difference is the absence of the 

 digestive cells, i. e., those that contain the varicose swollen mycelium. No evidences 

 were found in the Marattiaceae of the destruction of the fungus by the cells of the 

 host and it is likely that the endophyte in these green prothallia is more nearly a 

 true parasite than is the case in the saprophytic gametophytes of the Ophio- 

 glossaceaj. In the infested cells of the green gametophyte the starch and chroma- 

 tophores are destroyed by the action of the endophyte, but the nucleus of the cell 

 remains intact. 



THE SEXUAL ORGANS. 



THE ANTHERIDIUM. 



1 he development of the antheridium, except for the details of spermatogenesis, 

 was correctly described by Luerssen and Jonkmann for Marattia and Angiopteris. 

 The other genera agree closely with these in the essential structure of the antherid- 

 ium. The development of the antheridium in the Marattiaceae agrees very closely 

 indeed with that of Ophioglossum. 



J d 



Fig. 97.— Development of the antheridium in Danxa. 

 A. Section of prothallium, bearing antheridia on both surfaces. X8o. 

 B-H. Longitudinal sections. X300. -Z-a, D.elliptka; the others, Z).;ama,cen5». 



The mother cell of the antheridium, as in Ophioglossum, divides first by a 

 periclmal wall mto an outer cell, the primary cover cell, and an inner one, from which 

 the mass of spermatocytes is developed (figs. 96, 97). The mother cell of the anther- 

 idmm shows much the same variation in form as that oi Ophioglossum, sometimes 

 being relatively broad and shallow and at other times deeper and narrower (fig. 96 

 ' ^V u /' T-°2 '" the inner cell is usually transverse, but in the broader 

 type of antheridium this first wall may be longitudinal. The primary wall is followed 

 by a second one at right angles to it and the four cells thus formed are again divided 

 so that there result eight nearly equal cells. The first wall occasionally is somewhat 

 oblique, but even ,n such cases the regular quadrant and octant walls arise at right 



