XI. A NEW SPECIES OF FERN {POLYSTICHUM 



JENNINGSI). 



By L. S. Hopkins. 

 (Plate XXXVII.) 



Polystichum Jenningsi sp. nov. 



Stipe 2.2-2.4 dm. long, chaffy on encire length, with scales of va- 

 rious sizes, deeply grooved on outer side, the groove continuing along 

 the rachis and into the midrib of pinnae. Rachis densely clothed with 

 pale linear-lanceolate scales, which are lighter than those of the stipe. 

 Blade 1.7-2 dm. wide, 7.6-8.6 dm. long, proliferous, lanceolate, pin- 

 nate, with the lower pinnae again pinnate only so far as the first pair 

 of pinnules is concerned. Pinnae, lowest pair 2-2.5 cm. wide, 9-10 

 cm. long, broadest at the base, pinnatifid, gradually becoming serrate 

 towards the acuminate apex, the under surface bearing numerous 

 pale chaff-like scales, the upper (outer) surface sparsely covered with 

 pale linear (almost capillary) scales, the lowest pair being at about 

 right angles to the rachis, while those of the middle portion of the leaf 

 point obliquely upward; pinnules serrate, with each serration ending 

 in a spine 0.25-1.5 mm. long, sori 1-12 on each segment, large, midway 

 between midrib and margin, strongly confluent when mature. 



Type in the Herbarium of the Carnegie Museum, Pittsburgh, Pa. 

 Paratype, collected at the same time and place, number 2991 in my 

 herbarium. Type locality, Nisqually River, near Longmire Springs, 

 Mt. Ranier National Park, Washington. 



The new species is easily separated from most members of the genus. 

 In fact its size alone would probably distinguish it at once from all 

 save the var. inciso-serratum of P. munitum, as it is easily larger than 

 all other species, which occur in the United States. The dimensions 

 given are the actual measurements of the two fronds which have been 

 studied. The plant probably varies somewhat on either side of the 

 dimensions given. It could never be confused with the species P. 

 lonchitis, P. munitum, and P. acrostichoides, which are simply once- 

 pinnate. It is equally distinct from those species which are fully 



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