XXIIl] 



SPOROCARP 



183 



pointing inwards. Each receptacle, as in Pilularia, is closely invested by an 

 "indusium," and the structure is shown in section in Fig. 466, G. H 



Fig. 466. Marsilea quadrifolia L 



young leaf. /; the mother cell or apicii cell of a ^poiocaip: 



sorus, and soral canal. G, trans, sec. of flaps of a sporocarp. H, long. sect, oi same : ac, ai[-canal : 

 db, dorsal bundle : qr. gelatinous ring : i.ind. inner indusium : lb, lateral branches of dorsal bundle : 

 M/, twig of a lateral branch of dorsal bundle: masp, megasporangia : masp, mother cells of. 

 megasporangia : misp, microsporangia : imv, median wall: o.ind, outer indusium : pab, placental- 

 bundle: /-a/^r, branch of same: .re, soral canal : y//;, bundle of stalk of sporocarp. (.-i-£ x about 25O: 

 G, //X45.) (After Duncan Johnson, from Engler and Prantl.) 



