FLORA OF THE DISTRICT OF COLUMBIA. 55 



6. CHEILANTHES Swartz. Lip-pern. 



1. Cheilanthes lanosa (Michx.) Watt. 



Earthy crevices of cliffs or rocky bluffs; rare; vicinity of Great Falls (both nides of the 

 river) and near Chain Bridge. Summer. Eastern U. S. (0. vestitn Swartz.) 



7. PELLAEA Link. 



1. Pellaea atropurpurea (L.) Link. Cliff-brake, 



Crevices of dry sunny cliffs or on walls, preferring limestone; several scattered 

 stations, abundant in only one or two localities. Summer. N. Eng. to Minn., the 

 Mexican border, and Fla. 



8. ADIANTUM L. Maidenhair. 



1. Adiantum pedatum L. 



Rich, well-drained, rocky, deciduous woods and shaded hillsides; common. Sum- 

 mer. Most of temperate N. Amer., the western form differin? subscecifiraUv 



9. CAMPTOSORTJS Link. 



1. Camptosorus rhlzophyllus (L.) Link. Walking fern . 



Shaded mossy rocks in cool situations; several localities along the Potomac, prin- 

 cipally above Cabin John; also at I^aurel; rare. Que. to Ga., westward. 



10. POLYSTICHUM Roth. 



1. Polystichum acrostichoides (Michx.) Schott. Christmas fern. 



Moist woods and cool shady banks; abundant. About June first. Eastern N. Amer. 

 (Aspidium acrostichoides Swartz.) 



A colony is shown in plate 12. 



11. ANCHISTEA Presl. 



1. AncMstea virginica (L.) Presl. Chain fern. 



Swamps; infrequent, the known localities all in the eastern part of the range. Late 

 summer. Eastern N. Amer. (Woodwardia virginica J. E. Smith.) 



12. ASPLENIUM L. Spleenwort. 



Blades pinnatifid, or pinnate only near the base, the apex slender, long-attenuate. 



Stipe brown below, green above; rachis green 1. A. pinnatlfiduin . 



Stipe and rachis dark purplish brown 2. A. ebenoides. 



Blades 1-3 times pinnate, the apex not loa- attenuate. 

 Stipes and rachises reddish or purplish l:)rown throughout; blades linear, once pin- 

 nate only. 

 Fertile leaves rigidly erect, 20-40 cm. long; sterile leaves short, spreading; seg- 

 ments more or less auricled 3. A. platyneuron. 



Fertile and sterile leaves alike, all spreading, much narrower, 7-20 cm. long; seg- 

 ments not auricled 4. A. trichomanes . 



Stipes green from a dark brown base; rachises green; blades 2 or 3 times pinnate or 

 pinnatifid, more or less triangular fi. A. montanum. 



1. Asplenium pinnatifidum Nutt. 



Crevices and earth pockets of shaded cliffs; Virginia shore of the Potomac several 

 milesbelowGreat Falls; very rare. Summer. Conn, to Ga., westward. 



2. Asplenium ebenoides R. R. Scott. Scott's spleenwort. 

 Crevices of shaded rocks; two records, Plummers Island and Virginia shore of the 



Potomac near Little Falls. Summer. Vt. to Va., Mo., and Ala. ; abundant only in the 

 last state, where it is self -perpetuating. 



