50 A TEXT-BOOK OF BOTANY. 



a conidiospore is formed (Fig. 27, A; Fig. 28, A). The process 

 of division at the end of the conidiophore continues from below 

 until a chain of conidiospores is formed. The conidiophore fre- 

 quently branches, so that a fan-like series or group of conidia or 



FIG. 27. Pcnicillium, a green mildew. A, richly branching mycelium with conidio- 

 phores; B, enlarged view of conidiophore showing chains of conidia; C, D, E, F, successive 

 stages in the development of a perithecium; G, H, J, development of asci; K, groups of 

 asci containing, from 4 to 8 ascospores; L, ascospores seen from the side and showing char- 

 acteristic markings. After Brefeld. 



conidiospores is produced (Fig. 27, B ; Fig. 28, A}. The conidia 

 are usually some shade of green, but finally they may become more 

 or less brown. They are thin-walled, quite small, and so light 

 that they float freely in the air. If a colony is inhaled it gives 



