300 



BOTANY. 



398. Until Stall 1's researches* showed the existence of 

 sexual organs in Collema, they were entirely unknown among 



lichens. He discovered, deeply 

 imbedded in the tissue of the 

 plant, an organ composed of a 

 spirally coiled hypha- branch, and 

 a vertical septate portion, which 

 rises to, and projects above, the 

 surface ; the spirally coiled por- 

 tion he called the ascogonium, 

 and the vertical portion the tri- 

 chogyne. The whole he regarded 

 as a species of carpogonium (Fig. 

 207, A, c, and d). He observed 

 spermatia adhering to the pro- 



spermagonium, from which sperma- j ec tin or portion of the tricllO- 

 tia are escaping. Magnified. After r 



Tuiasne. gy n j some of these united them- 



selves to the trichogyne by means of a tube (C, Fig. 207). 

 The result of this coalescence was the withering and disap- 

 pearance of the 

 cells of the tricho- 

 gyne, and the 

 growth and devel- 

 opment of the as- 

 cogonium. The 

 latter process takes 

 place as follows : 

 "The cells of the 

 ascogonium first of 

 all increase in size, 

 and then undergo 



snlf rf 



nc,., - 207. Sexual organs of Collema micronfiyllvm. A, 



as a re- section of thallns; o, , hyphse ; b, b, the Noctoc-like 

 g Rid 'a ; c, ascogonium; d, the esserted trichogyne. B, 

 tlie ppermatia, b, surrounding theexserted tricho^yne, a. 

 SDirfll arrano-pmonf ^ coalescence of a spermatium, b, with trichogyne, a. 

 iriangement All the figures magnified, 5 and C much more thin A. 



of the cells be- AfterSta hi. 



comes less and less conspicuous, for the cells gradually sepa- 



Ueber die Geschlechtliche Fortpflanzung der Collemaceen," 1877 

 (On the Sexual Organs of the Collemaceje). A brief synopsis of Stahl's 

 results appeared in the Qr. Jour, of Mic. Science, October, 1878. 



