CARPOPHTTA. 



157 



326. The crossing and branching filaments soon send up 

 many vertical branches, in which partitions form at regular 

 intervals. The cells thus formed are at first oblong and 

 cylindrical, with flattened ends; but the topmost one soon 

 becomes rounded at its extremities, and the others follow- 

 in quick succession, thus giving rise to a row of cells, the 

 spores, or conidia (Pig. 79). These fall off and germinate 

 at once by pushing out a tube, which gives rise to a new 

 plant. 



327. The sexual process in most species takes places late in 

 the season. Two filaments crossing each other or coming 



Fio. 80. Fio. 81. 



Fio. 80.— The sexual process in a Blight (Erysiphe). n, jointed threads; 6, 

 antheiid; c. carpogone; d, young spore-fruit; e, older spore-fruit. Magnified. 



Fio. 81.— Ripe spore-fruit of Willow-blight (Uncinula adunca). The append- 

 ages are curved or hooked. Magnified. 



into close contact swell slightly and send out from each a 

 short branch; one of these becomes the carpogone (c, Pig. 

 80). From the swollen part of the other filament a corre- 

 sponding branch is given off, which grows up in contact 

 with the carpogone and becomes the antherid {b, Pig. 80). 

 328. Fertilization at once takes place, by the direct union 

 of protoplasm. Eight or ten branches grow out Just below 

 the carpogone, and growing upward soon completely cover 

 it with a cellular coat which eventually becomes hardened 

 and turns brownish in color, constituting the pericarp of 

 the spore-fruit (Pig. 81). 



