Grinnellia americana, Harv. 19 



and possess a clear granular appearance. Presently they 

 enlarge (Fig. %6cp)^ passing through an elongated oblong- 

 elliptical form (Fig. 36 c') to a true oval or spherical shape 

 (Fig. a6 m). As the spores gradually increase in size, they 

 acquire a reddish colour which finally becomes a lake-red, 

 the characteristic colour of all mature spores of Grinnellia. 

 This process is repeated by every one of the sporifercus 

 filaments developing from the large central basal cell, in this 

 way giving rise to a very large number of carpospores, 

 averaging from 300 to 400, in every mature cystocarp. The 

 stimulation resulting from fertilization of the young cystocarp 

 is manifest not only in the origin and active growth of the 

 sporiferous filaments, but also in the rapid development of 

 other portions, such as the pericarp, basal cortical tissue and 

 sterile filaments (Fig. 21). 



From the moment the joint-cell at the base of the procarpic 

 branch begins to enlarge and acquire dense protoplasmic 

 contents, the growth of the pericarp is accelerated. The cells 

 on the upper surface of the cystocarp multiply rapidly and 

 become elevated by the growth of tissue in the fruiting portion 

 of the young cystocarp. As this surface-tissue, which is to 

 form the pericarp, further develops, it is apparent that its 

 irregular arrangement of cells is becoming regular, and that 

 a number of filaments, growing apically, are united with each 

 other by lateral branches. These pericarpic filaments not 

 only branch in the surface-plane of the pericarp, but also at 

 right angles to that plane, forming two- to three-celled branches 

 which are connected with the terminal cells of the sterile 

 filaments within the cystocarpic cavity (Fig. 18 sp). The 

 branches from the pericarpic filaments decrease as the filaments 

 grow outward and upward until their apices are in contact and 

 form a circle about an open portion over the central region 

 of the cystocarpic cavity. These filaments now change the 

 direction of growth, which had previously formed an angle 

 of 60° to 75° with the surface-plane of the frond, so that they 

 grow almost at right angles with that surface (Fig. 22 cr). 

 The apical cells divide four to six times and growth dis- 



