BENEDICT : ANTROPHYUM 447 
natural relationships. By a combination of the characters of sori- 
ation and spore-form, separation into four subgenera is readily 
made. The use of microscopic characters may be carried still fur- 
ther. The Asiatic species are easily divided into groups and to 
some extent, into species according to the shape of the soral par- 
aphyses. By this means certain species, otherwise easily confused, 
may be separated without difficulty. 
Four of the five African species, which possess several well- 
marked distinctive characters, have been separated as a new sub- 
genus, Antrophyopsis.* The only other African species known, 
A. immersum, seems to belong rather with the type section. 
The terms “ diplanate ” and “ triplanate’”” have been used for 
the spores instead of the usual “reniform” and “ sphaero-tetrahe- 
dral”’ as being of more exact significance, since they relate not to 
mere variable form but to systems of spore-cleavage. 
Synopsis of subgenera 
Soriation in mature fronds completely reticulated, superficial or slightly raised ; spores 
diplanate ; paraphyses present ; costa vestigial, marginal veinlets free to the edge 
of the frond ; stipe-scale cell-walls papillose (all?). 
, Antrophyopsis (African) * 
Soriation of simple or branched lines which may be more or less interconnected 
ut never completely reticulated, superficial or immersed in grooves; spores 
diplanate or triplanate, paraphyses present or absent ; costa complete or vestigial, 
marginal veinlets usually anastomosing with the anterior veinlets to form closed 
areolae; stipe-scale cell-walls smooth. 
Spores diplanate, paraphyses pyriform; costa complete. 
@ ScoLiosorus (American) 
Spores triplanate. : 
porangia in three or four long grooves on each side of the complete costa and 
parallel to it; paraphyses wanting. @ POLYTAENIUM (American) 
Sporangia, except in the three narrowest forms, in branched lines, more or less 
connected ; paraphyses present or absent ;, costa complete or vestigial. 
3 EUANTROPHYUM 
Paraphyses wanting ; costa complete or nearly so. 
Costata (American ) 
Paraphyses present; costa vestigial, Lcostata (Old World) 
The American section of the genus Axtrophyum comprises 
nine species separable into three subgenera as noted in the group 
Synopsis, according to (1) soriation, and (2) spore-form. All are 
alike in having a complete or nearly complete costa, a character 
distinguishing them from all the Old World forms, some of which, 
A 
*Type, 4. Boryanum (Willd.) Spr, 
