CHAEACTBES OF TRIBES AND GENERA. 213 



sometimes so deep as to give tlie indusiam a bi-lobed 

 cliaracter, while in others it is scarcely evident and the 

 indusium is then nearly orbicular and thus characteristic of 

 Pohjstichum. In the " Species Pilicum " Lastrea ranks only 

 as a section of Nei^lirodmm ; 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 

 163, 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 Aspidlnni., 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 decumbeiit, in some 

 becoming arhoroid {Dryopteris) . 



1. — Oeeopteeis Group. 

 Fronds lanceolate pinnate ; pinnte more or less deeply pinnatifid. 



Veins pinnate in the lobes ; venules simple, rarely forked. 



Sp. L. decursivo-pinnata {Ivze.) (v v.) {L. decurrens 

 J. Sm.) ; L. exigua (Kze.) ; L. viscosa (/. Sm.) ; L. sancta 

 (Sw.) (v v.). 



Obs. — This has hitherto been ranked among nonindusiate 

 Ferns, but ha-ving observed small indusia on cultivated 

 plants, I therefore place it here. 



