392 



(Edogoniales 



upper cell is very often one which, owing to repeated previous divisions, 

 possesses a number of apical caps (vide figs. 247 F; 249 B and G; 250 A), and 

 after division it contains most of the protoplast of the original mother-cell. 

 The supporting cells of some species of (Edogonium are decidedly swollen 

 [consult fig. 249 G of (E. lautumniaram Wittr. and fig. 250 A of CE. Borisianum 

 (Le Cl.) Wittr.]. The oogonia are ovoid, globose or depressed-globose in 

 outward form and in (Edogonium they occur singly at intervals along the 

 filament or in series of from 2 to 10. When seriate the oogonia arise in 

 basipetal succession by the repeated divisions of the lower or supporting cell. 



f 



A 



Fig. 246. A and J5, young plants of (Edogonium Howardii Gr. S. West, x 520. C and D, adult 

 plants of (E.inconspicuum Hirn, x 500. E H, developmental stages (from the zoogonidium) 

 of (E. rufescens Wittr. var. Lundellii (Wittr.) Hirn, x 372. I, young plant of (E. Virce- 

 burgense Hirn, x372. (EI, after Scherffel.) Note the form of the basal cell in all these 

 figures. J", young plant of Bulbochsete intermedia De Bary showing the basal cell (b) and the 

 growing bristle (br) which is the first cell formed from the basal cell. K, part of a branch 

 of B. intermedia showing the first division of an intercalary cell resulting in the formation 

 of a laterally placed bristle (br). J and K, x 300 (after Hirn). 



In the genus BulbochtBte the formation of the oogonium is not so simple 

 as in (Edogonium since it arises as the result of a double division. The first 

 division results in a transverse wall which cuts off a supporting cell from a 

 primary oogonium-cell (fig.. 247 Apr). The latter bulges outwards at its 

 upper end, the new wall bursting through the old mother-cell-wall and 

 forming a swelling under the bulbous base of the bristle. This swelling is 

 the young developing oogonium and about the time it attains its full size the 



