CHARACTERS OF TRIBES AND GENERA, 913 
sometimes so deep as to give the indusiam a bi-lobed 
character, while in others it is scarcely evident and the 
indusium is then nearly orbicular and thus characteristic of 
Polystichum. In the “ Species Filicum " Lastrea ranks only 
as a section of Nephrodiwm ; the author thus not admitting 
the difference between anastomose and free venation to be 
of sufficient generic value to warrant the separation of the 
two groups of species ; in the section Lastrea 115 species 
are described, in the “ Synopsis" the number is raised to 
158, of which 65 have Mr. Bakers initials affixed, and in 
the Appendix 46 species are enumerated, a few of which 
are for the first time described as new species, but the 
greater number consists of removals from Aspidium, the 
specific name being changed in many cases. 
Lastrea as here restricted contains about 100 species, of 
which 65 have been examined by me in a living state. 
The difference in the position of the sori and forms of the 
indusium has led to the species being arranged under a 
dozen or more genera by different authors, none of which 
have sufficient character to warrant their adoption. 
Sect, 1.—Vernation fasciculate, erect or decumbent, in some 
becoming arboroid (Dryopteris). 
1.—OREOPTERIS GROUP. 
Fronds lanceolate pinnate; pinna more or less deeply pinnatifid. 
Veins pinnate in the lobes; venules simple, rarely forked. 
Sp. L. decursivo-pinnata (Kze) (v v.) (L. decurrens 
J. Sm.) ; L. exigua (Kze.) ; L. viscosa (J. Sm.) ; L. sancta 
(Sw.) (v v). 
Ons.— This has hitherto been ranked among nonindusiate 
Ferns, but having observed small indusia on cultivated 
plants, I therefore place it here, 
