FLORA OF THE UPPER SUSQUEHANNA. 187 



D. spinulosa (Retz) Kuntze. Simni lose Shield Fern. Not 

 common. Found throughout, but much less common than the 

 following sub-species. Fronds tall, ovate, bipinnale, the pin- 

 nules with spinulose teeth. The fronds are produced in early 

 sprmg, several in a clumj-) and are half evergreen. {Aspuiium 

 spinulosum Svv. ) 



O. spinulosa intermedia iMuhl.) I'nderw. Siim l<»>k wSimii.- 

 Fkkn. ( )ne of the commonest of ferns. Found in woodlands 

 wet or dry. Resembles 1>. spinu/osa, but with the pinna- and 

 l)innules more crowded and finely dissected. {A. spinitlo- 

 sinii, var. tutey-inediiiiii D. C. Eaton.) 



D. spinulosa dilatata (Hoffm.) Underw. Much less common 

 than the type and usually found at higher elevations. (Aspui- 

 I'ltm spniulosioii, var. dilatatimi Ho^k. ) 



It is a difficult matter for the beginner to properly separate 



Dryoptcris- spi7iulosa from its varieties. The fronds vary 

 somewhat in shape and it is only with an abundance of material 

 that one can distinguish the limits of the forms. 



O. Boottii (Tuckerm. ) Underw Bu(>tt'> Shield iern. Rare. 

 Susquehanna, Gra^'t's. Pond Brook. Cluie. The only stations 

 reported. In appearance this tern is about half way between 

 D. sphutlosa and the following. Further study of the forms re- 

 ferred to these two ferns will doubtless discover more stations 

 for the present species. {Aspidnnn A'(V/// Tuckerm.) 



D. cristata (L.) A.Gray. Crest Fern. Crested Shield-Fern. 

 Plentiful in swampy woods. Fronds tall snd narrow, lanceolate 

 in outline, pinnate, their divisions pinnatifid. the lowest piir of 

 ])innic triangular. Tne sterile fronds are usually shorter and 

 broader than the fertile and less erect {Aspidiidn oisttUuin 

 Sw.) 



D. cristata Clintoniana (D. C. Eaton) Underw. Rare. Swamp 

 near the city of Hinghamton, Cliite Unadilla Forks. Kro'wu. 

 The only stations recorded. The fronds of this fern are in every 

 way larger than the preceding, which it otherwise much re- 

 sembles. Closer observation of our ferns will probably bring to 

 light other stations for this one. {Aspulium cristatuin, var. 

 CUntonianuni D. C. Eaton ) 



