122 



the Gulf States; also in Europe, Asia, China, 

 Japan and South Africa. 



Ecological and monstrous forms of this 

 species have been named alato-multifidum, 

 attenuatum, bifido-multifidum, Cambricum, 

 Churchiae, Columbianum, deltoideum, hasta- 

 tum, marginale, multifidum, platyiobum, 

 ramosum, rotundatum, semi-lacerum, and 

 sinuatum. The form Cambricum is the Welsh 

 polypody and forma rotundatum has round- 

 ended pinnules. Any of these forms are likely 

 to occur with the type. They are described in 

 the Fern Bulletin XIV, 33, 1906. 



182. Polypodium vulgare angustum Muell. Not 



common ; on shaded rocks. In the Alleghenies 

 from New York to Virginia. — Polypodium vul- 

 gare deceptum Maxon; P. v. biserratum Mills- 

 paugh; P. v. acuminatum Gilbert; P. v. oreo- 

 philum Maxon. 



POLYSTICHUM Roth. 



183. Polystichum acrostichoides Michx. Christ- 



mas Fern. Shield Fern. Abundant; espe- 

 cially in moist, rocky woodlands. Nova Scotia 

 and New Brunswick to Wisconsin, Iowa and 

 south to the Gulf States. — Aspidium acrosti- 

 choides Sw. ; Dryopteris acrostichoides Kuntze. 



The form crispa, Clute is a wavy-leaved 

 form occurring with the type; f. incisum 

 A Gray (P. acrostichoides Schweinitzii Beck) 

 is an incised form also likely to occur, f. mul- 

 tifida Clute is a form with deeply divided pin- 

 nules reported from Connecticut, New York 

 and New Jersey ; f. recurvatum Clute has the 

 pinnules recurved and the margins reflexed. It 



