DEVELOPMENT OF PLANTS 221 



the characteristic blue or brown color of the fungi. These ex- 

 tremely small and numerous spores float off in the air as an 

 invisible dust and quickly germinate under favorable conditions, 

 forming new mycelia. 



The male and female gametangia are very similar, short 

 branches that become closely intertwined (Fig. 143, A). The 

 fusion of the gametes is made possible through a dissolution of 

 the separating walls at the tips of the gametangia. The resulting 

 gametospore remains attached to the parent plant and germi- 

 nates at once, forming an irregular hyphal outgrowth (Fig. 143, 

 B, s) w^hich becomes completely overgrown by the hyphae of the 

 mycelium (Fig. 143, B, C). Thus is formed a solid body, known 



Fig. 143. Sexual reproduction of the Aspergillales and the formation of 

 the ascocarp or perithecium: A, meeting of the male, an, and female, 0, 

 gametangia. B, early stage in the development of the ascocarp. The gamet- 

 ospore has formed a series of branches, s, which are being surrounded by hyphae 

 (unshaded in the figure) from the mycelium. C, later stage seen in section. 

 The gametospore has formed a much-branched body, s, which is surrounded 

 by a closel}' interwoven mass of hyphae that appear in section as cells. — 

 After Brefeld. 



as the ascocarp or perithecium (plu. perithecia), that appears to 

 the eye as a minute grain of sand. During this growth numerous 

 lateral branches arise on the hyphae derived from the gameto- 

 spore and become transformed into asci as shown in Fig. 144, 

 A, B. The ascocarps finally decay and set free the ascospores 

 which develop a new plant or mycelium. Thus the entire life 



