259 
of Poronia punctata (Z.). 
formation of perithecia in nature. Up to the present, in 
stromata grown in pure cultures, only the very early stages 
have been observed, i. e. the small-celled knot of hyphae, 
enclosing the coiled Woronin’s hypha, although several 
specimens are more than two months old, and have been 
supplied with free access of air, and grown under varied 
conditions of illumination and temperature. Possibly the 
time of year is the explanation of this check in the develop¬ 
ment, and the asci are by some special adaptation of the 
Fungus only capable of being formed in the autumn months. 
This point can naturally only be decided by a further con¬ 
tinuation of the cultures throughout the coming year. What¬ 
ever may be the true explanation of the details in the formation 
of the perithecia of Poronia , it seems clear that in this genus 
we have a very interesting example of Fungi with a Woronin’s 
hypha, which as De Bary has already pointed out 1 form 
a connecting link between the archicarps of Collema and 
Poly stigma and the sporocarps of Claviceps. If we there¬ 
fore regard these archicarps on the one hand as the homo- 
logues of the Woronin’s hyphae on the other hand, we 
can give the position of Poronia as intermediate between 
Poly stigma and Xylaria. In Poly stigma the stroma is a 
somewhat less defined structure than in Poronia 2 , i. e. it 
consists of a fleshy cushion-like mass of tissue on the surface 
of the infected leaf, and in this mass the perithecia are 
embedded, whilst on the contrary the stromata of Xylaria 
are still more definite, more elaborate and horny structures 
than in Poronia. 
This suggested position of Poronia is illustrated by a com¬ 
parison of the details of the archicarp and its homologue and 
by the consideration of any other reproductive bodies which 
are formed in the respective genera ; thus :— 
In Collema we find a coiled archicarp with a prominent 
trichogyne, which penetrates to the outer surface of the thallus, 
and there fuses with the spermatia, which are formed in 
1 De Bary, loc. cit., p. 236. 
2 Cooke, Handbook of British Fungi, p, 803. 
