260 Dawson.—On the Biology 
definite organs, the spermogonia—that is, in this genus, there 
is a clearly marked sexual act. These facts have recently 
been confirmed by Bauer 1 . 
In Polystigma , a similar coiled archicarp with a trichogyne 
is present. Here, too, are found spermogonia with spermatia, 
which were seen by Fisch 2 adhering to the trichogyne, but 
the union of the two was not observed. 
In Poronia , we again find a coiled hypha (quite com¬ 
parable to the archicarp of Poly stigma), with a more or less 
degenerate trichogyne-process. In this genus, however, the 
spermogonia with spermatia are not developed, so that there 
can be no question of the sexual function of the trichogyne. 
In Xylaria , this functionless trichogyne appears to have 
been dispensed with, as well as the spermogonia and spermatia. 
If this series of forms, and the implied homology of the 
organs in question be a correct view of the case, we must 
regard the ascospores of Poronia as formed parthenogenetically 
by intermediate stages from an organ, which represents the 
archicarp, which in certain other forms is sexually functional, 
but which in Poronia has lost that power. If further details 
of the stages between the coiled Woronins hypha and the 
ripe asci could be determined, it is conceivable that later 
fusions of nuclei might be found to occur, which might be 
regarded as a secondary sexual act replacing the more obvious 
one, which has been lost in the earlier stage. This, pre¬ 
sumably, would accord with Dangeard’s 3 view, that the fusion 
of the two original nuclei in the young ascus represents the 
true sexual act in the various Ascomycetes, which he investi¬ 
gated 4 . No such fusions have been seen, however, in Poronia. 
The Botanical Laboratory, Cambridge, 
March, 1900. 
1 Bauer, Zur Frage nach der Sexualitat der Collemaceen, Ber. d. Deutsch. Bot. 
Ges., vol. xvi, 1898. 
2 Fisch, loc. cit. 
3 For a full discussion of the views of Harper and Dangeard upon the Sexuality 
of the Ascomycetes, see Wager, On the Sexuality of the Fungi, Ann. of Bot. xiii, 
Dec., 1899. 
* See Dittrich, Cohn’s Beitrage, viii, 1898. 
