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 ibe peeens ; igh 
diplanate ; paraphyses present ; costa vestigial, margina 
of the frond ; stipe-scale cell-walls papillose (all?). 
2 Antrophyopsis ( —— * 
Soriation of simple or branched lines which may be more or less interconnect 
ee in ok oni 
vestigial, 
diplanate or triplanate, paraphyses present or absent ; 
marginal veinlets usually RN with the anterior veltilets to form clo 
areolae ; stipe-scale cell-walls s 
Spores diplanate, paraphyses satan: costa complete. 
3 ScoLiosorus (American) 
Spores — 
Sporangia in three or four long grooves on each side of the complete costa and 
sais to it; paraphyses wanting. PoLYTAENIUM (American) 
porangia, except in the three narrowest forms, in branched lines, more or less 
connected ; paraphyses present or absent ; costa complete or vestigial. 
EUANTROPHYUM 
Paraphyses wanting ; costa complete or eon Os 
Costata (Aon can) 
Paraphyses present; costa vestigial. Ecostata (Old 1 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, 
ee ene ee eee 
* Type, A. Boryanum (Willd.) Spr. 
