XLI] GROUPING OF ASPIDIEAE i37 



gressions seen in phyla quite distinct from the Aspidioid Ferns. The grouping 

 of the genera of the Aspidieae according to their soral characters will there- 

 fore resolve itself as follows : 



I. SORI WITH RENIFORM INDUSIUM. 



/^rj^/Zmj- Adanson, 1763 741 species. 



L?iersse7iia K\x\\n, iS?>2 i species. 



Fadyeuia Hooker, 1 840 i species. 



Mesochlaena R. Brown, 1838 i species. 



Didymochlae}iaJ:>Qswd.u^,i2,ii i species. 



II. SORI WITH PELTATE INDUSIUM {INDUSIUM SUPERUM). 



Aspidmm Swa^rtz, iSoi 138 species. 



P^/)/.s-/zV/w;« Roth, 1799. Schott, 1S34 112 species. 



Q/^/^/^///j- J. Smith, 1846 2 species. 



^^^^^^fl'^rrw J. Smith, 1875. Maxon, 1905 ... 2 species. 



P/m«^w/)/^/^(^/rt Presl, 1836. Underwood, 1902 ... 10 species. 



Cyclodium Presl, 1836 2 species. 



III. SORI EX-INDUSIATE, OR SHOWING VARIOUS DEGREES OF ABORTION. 

 Many species of Dryoptcris, and particularly the old genera Mcniscium 



and PJiegopteris^. 



Aerophones Presl, 1 836 i species. 



PlecosorHsYi^,\Z^o-^2 3 species. 



IV. SORI ACROSTICHOID. 



Polybotrya Humb. and Bonpl., Willdenow, 18 10 30 species. 



StenosemiaVxQ.sX,i%i6 2 species. 



Z^/'^t7/////j-.Kaulfuss, 1824 the pinnate species. 



BIBLIOGRAPHY FOR CHAPTER XLI 



667. Mettenius. Filices Horti Lipsiensis. Leipzig. 1856. 



668. Mettenius. Farnkrauter, iv. Frankfurt. 1858. 



669. LUERSSEN. Die Farnpflanzen, Rab. Krypt. Flora, ni. 1889. 



670. DiELS. Engler and Prantl, i, 4, p. 167, etc. 1902. 



671. Hannig. Vorkommen von Perisporien, Flora, Bd. 103, p. 340. 191 1. 



672. Bower. Studies II, Ann. of Bot. xxvi, p. 269. 1912. 



673. Davie. Peranema, Ann. of Bot. xxvi, p. 245. 1912. Also xxx, p. loi. 1916. 



674. C. Christensen. Monograph of the genus Z'ry^JjzJ/i'r/j-. Copenhagen. 1913 onwards. 



675. Frau Eva Schumann. Die Acrosticheen, Flora, Bd. 108, p. 201. 191 5. 



676. Von Goebel. Organographie, ll, 2, pp. 959, 1148. 1918. 



677. Bower. Studies VII, Ann. of Bot. xxxii, p. i. 1918. 



1 Diels (E. and P. i, 4, p. 167) remarks in relation to the genus Nephrodiiiin {Dryopleris): "The 

 insecurity of the diagnobtic characters founded on the indusium is nowhere more prominent than here. 

 Before all it is plain that the absence of this organ within the Aspidieae has no systematic value.'' 

 We may readily assent to this from the point of view of the herbarium-systematist. In the practice 

 of diagnosis and classification it may be useless : nor is it here possible to designate strictly under 

 any general name those species of Dryopteris that are actually ex-indusiate. But from the point of 

 view of Comparative Morphology the ex-indusiate condition has a definite significance, since it has 

 opened the way to the recognition of the Acrostichoid development. 



