THE FERN BULLETIN 



77 



Acrostichums and Antrophyums and the resemblance 

 is so close, in some cases, that even eminent fern stu- 

 dents have never quite agreed as to the disposal of the 

 species, placing them now in one genus and again in 

 another. Among the synonyms of the different species 

 of Hemionitis one finds a dozen or more different 

 genera cited, showing with what diverse groups the 

 species have been at times supposed to be allied. In 

 this list Antrophyum is first with Gymno gramma a 

 close second. 



Most of the ferns with which the collectors in the " 

 United States are familiar have their sporangia 

 grouped in masses at the tips or on the backs of the 

 veins. The bracken (Pteris) is probably the most 

 familiar exception to this, but even in the bracken, 

 the sori may be assumed to be at the tips of the veins 

 and only spilling over, as it were, along the marginal 

 vein that unites the vein tips. In the tropics, however, 

 and to some extent in the southwestern part of the 

 United States, we meet with ferns whose sporangia 

 instead of being arranged in groups, are scattered all 

 along the veins, often in dense lines. Occasionally, 

 too, they are found on the under surface of the frond 

 between the veins. 



In this group belongs the species of Hemionitis. 

 The genus, itself, is principally distinguished by hav- 

 ing palmate fronds, or fronds that approach that form, 

 and reticulated veins covered with sporangia. Such 

 specific names as palmata, cordifolia (heart-leaved), 

 Hederaefolia (ivy-leaved), and sagittata (arrow- 

 shaped) applied to the different species indicate some- 

 thing of this general and generic appearance. 



As at present recognized the genus consists of about 

 eight species, two of which occur in parts of the East 



