268 



EMBEYOGENY IN FUNGI. 



observed, and in Zyzygites megalocarpus as well as in species of 

 Ehizopus (R. nigricans), the formation of a compound spore by the 

 complete amalgamation of two cells has occasionally been noticed. 

 This compound spore is termed a zygospore (^uyiv, a yoke). The 

 bodies called ajstidia (xiidTig, a bladder), seen in Fungi, are supposed 

 to represent antheridia ; while others called oogonia (dibv, an egg, and 



Fig. 473. Kg. 474. 



yovos, offspring), are reckoned as equivalent to archegonia or sporangia, 

 in which, after the action of the antheridia, a fertilised spore is 

 formed, which is denominated an oospore. 



In Lichens, which are Thallogens, reproductive bodies called spores 



Fig. 475. Fig. 476. Pig. 477. 



occur in thecse or asci, which are united in the form of open discs or 

 apothecia {a-jrh, from, Shun, box), and in hollow conceptacles called 

 perithecia ('Jti^i, around). On the thallus of lichens smaller hollow sacs, 

 called spermagones (ff^rsj/ia, seed, yovog, offspring), also occur (fig. 473). 

 These when cut through show bodies inside called spermaiia (fig. 

 474), which some consider as representing antherozoa or sperma- 

 tozoids ; they are supported on stalks called sterigmata (aTri^iy//,cx,, a 



Fig. 473. Two Spermagones on thalli of Lichens. Fig. 474. Spermagones of a Lichen 

 cut through, showing outer filaments, /(hyplm), with rounded green cells, g (garddia) ; in the 

 interior sterigmata and spermatia ; opening at top, o. Fig. 475. Sterigmata, a, and sper- 

 matia, 6, of Cladonia flmbriata. Fig. 476. Pycnides of a parasitic Lecidia on thallus of a 

 Cladonia. Fig. 477. Basidia, a ; stylospores, h ; free stylospores, c, from pycnides of same 

 Lecidia, 



