HEMIONITIS CORDATA. 



mi 



although they are less distinct than these. It is a very well 

 marked genus, and admirably characterised by Mr. Brotfn, its 

 nearest affinity to fructification would appear to be in Crypto- 

 gramma, which differs chiefly in having the margins involute, 

 not abruptly inflexed, and in habit. In Lomaria too, there is a 

 similar arrangement : the sori occupying the upper part o 

 the secondary veins PI. CXXXVIII. Fig. II. ,3. presenting a 

 tendency towards occupying their whole length. Hence two 

 modifications of form occur, in which all the veins are in 

 soriferious : 



1 st. veins distinct. 



2nd. veins running into an intro-marginal one, to this 

 belongs Pteris. 



Distinction may likewise be made between those with ac- 

 tually continuous sori, and those which have them only con- 

 tinuous by approximation. 



Hemionitis cordata. The venation of this species is curious, 

 it is reticulate, but that of the margins is incomplete, and it 

 is only towards this that clavate- erased veins occur. 



As in Ophioglossum, it is decidedly of a less perfect nature 

 than the generality of the order. 



As in that plant, the central vein is Imperfect, and not to 

 be distinguished in the upper part of the frond. 



The fructifying frond is smaller than the rest, but its stalk 

 is much longer. 



Upper surface estomatose, under surface with largish, 

 stomata, the mouth projecting beyond the surface. 



The whole of the under surface corresponding to the veins, 

 produces capsules, and what is curious, these in one and the 

 same place, are of various ages. 



It may subsequently be found that more natural divisions 

 will be indicated by the venation than by any other single 

 character. 



Diplazium. In this I find that the midrib, or rather primary 

 vein of the frond, as well as of the minor divisions, are smooth, 



4 c 



