448 CRYPTOGAMIA FILICES. 



HAB. Dry rocky places. April. A small tree ; leaves sometimes ter- 

 nate ; berry small , blue. 



T. prnstrata : leaves imbricate in four rows, ovate, submucronate, gland- 

 ular in the middle, appressed ; berries tubercular ; stem prostrate, 

 creeping. 



HAB. Gravelly shores. A shrub with very long creeping branches ; 

 berries longer than No. 2. 



410. TAXUS. Yew. 



T. canadensls : leaves linear, disticnous, revolute on the margin ; sterile 



receptacle globose. 

 HAB. Shady rocks. April. Shrub evergreen, 2 4 feet high ; berries 



red. 



CRYPTOGAMIA. 

 FILICES. 



Oenera. 



* Capsules furnished with an articulated elastic ring, transversely 

 opening. 



411. POLYPODIUM. Sori (small clusters of capsules) rouixh'sh, 

 scattered. Involucrum 0. 



412. HYPOPELTIS. Sori roundish, having a cup-shaped involu- 

 crum beneath, divided into 5 6 irregular segments. Capsules ses- 

 sile. 



413. ASPIDIUM. Sori roundish or elliptical, scattered. Involucrum 

 umbilicate, or opening on one side. 



414. ASPLENIUM. Sori linear, straight, more or less transverse. In- 

 volucrum arising from the lateral veins, and opening towards the 

 central nerve or rib. 



415. PTERIS. Sori in a continued marginal line. Involucrum form- 

 ed of the inflexed margin of the frond, opening inwards. 



416. ADIANTUM. Sori oblong or roundish. Involucra membrana- 

 ceous, arising from distinct portions of the frond turned in, opening 

 inwards. 



417. ONOCLEA. Sori indeterminate. Capsules covering the whole 

 lower surface of the frond. Involucrum resembling a berry, formed 

 of the frond, opening, but not expanding. 



* * Capsules destitute of a ring, vascular-reticulate, pellucid, ra- 

 diate at the tip, and substriate, longitudinally (and often externally) 

 opening. 



418. OSMUNDA. Capsules subglobose, pedicellate, striate, half-bival- 

 ved, paniculate. Involucntm 0. 



