102 



STRUCTURAL BOTANY 



spirally coiled body is derived almost entirely from the 

 nucleus of the mother- cell, while the cilia themselves, 



and perhaps the point 

 of the body to which 

 they are attached, are 

 formed from the pro- 

 toplasm. The spermato- 

 zoids are almost exactly 

 like those of Ferns, and 



go spinning through the 

 FIG. 46. Equisetummaximum; young water j n tne same way 

 antheridium. w, wall ; sp, tissue 



from which spermatozoids will be In fact there are some 



antheridia as well as 

 the spermatozoids agree in every respect with those of 

 the Horsetails. 



b. The Archegonia 



The first archegonia arise on the cushion-like part of 

 the prothallus ; as fresh lobes go on forming, additional 

 archegonia are developed at the base of each lobe (Fig. 

 45, a). The archegonia at first point downwards as in 

 the Ferns, but subsequently get turned upwards by the 

 growth of the lobes. The development of the individual 

 archegonium is almost exactly like that in some Ferns. 

 Usually no basal-cell is formed ; the mother-cell of the 

 archegonium divides at once into central cell and neck. 

 The central cell cuts off two canal-cells at the top, and 

 in the meantime the neck goes on growing. Here also 

 there are four rows of neck-cells, each row consisting of 

 three or four cells. The top four cells are very long, 

 and bend far back, leaving a wide opening between them 

 when the organ is ripe (see Fig. 47) 



