102 



STRUCTURAL BOTANY 



spirally coiled body is derived almost entirely from the 

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



and just that part 

 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. Equisetum maximum; young wa t er ill the same way. 

 antlieridium. w, wall ; sp, tissue 



from which spermatozoids will be In fact there are some 

 formed. Magnified about 200 dia- TiY> rriQ -in wVn'pTi tVp 



. / A />, T> 1 j_* \ -L O-L HO -L1J. \Y lllOU LUC 



meters. (Alter Bucntien.) 



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. 



O v 



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 mean time the neck goes on growing. Here also 

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

 three or four cells. The four cells at the top are very 

 long, and bend far back, leaving a wide opening between 

 them when the organ is ripe (see Fig. 47). 



