FLORA OF WASHINGTON AND VICINITY. 137 



GYMNOSPERMS. 



CONIFERiES. 



Pine Family. 



t Juniperua Virginiana, L. Red Cedar. Savin. 

 Male ameuts in April. 



t Pinus rigida, Miller. Pitch Pine. 



This species well illustrates the persistence of cones. On March 26, 1876, I made 

 observations on a large tree recently blown down in the vicinity of the Blair Road 

 and Sligo Creek. Cones in a good state of preservation were still adherent to the 

 trunk of the tree 4^ meters from the top, where it had a girth of half a meter. 

 As these cones were developed from the branches of the season, this affords some 

 idea of the length of time since the part of the tree to which they adhered consti- 

 tuted its summit. Aments in May. 



Pinus pungens, Michx. Table Mountain Pine. 



Near Rock Creek, opposite Crystal Spring. Some dozen fine trees. 



t Pinus inops, Ait. Scrub Pine. Jersey Pine. 

 Aments, end of April or first of May. 



t Pinus mitis, Michx. Yellow Pine. 

 Aments, middle of May. 



t Pinus Strobus, L. White Pine. 

 Aments, middle of May. 



Tsuga Canadensis, Carrifere. \_Aiies Canadensis, Michx.] Hemlock Spkucb. 

 Bluff's below Great Falls, Va. 



CRYPTOGAMIA. 

 VASCULAR CRYPTOGAMIA. 



EQUISETACE.aS. 



Horsetail Family. 



tEquisetumarvense, L. Common Horsetail. 

 Last week in April. 



tEquisetum hyemale, L. Scouring Rush. Shave-Grass. 



Common. A very large form, a meter in height, was found in a ravine above the 

 Receiving Reservoir, with spikes already formed, on the 17th of February, 1878. 

 June. 



FILICES. 



Ferns. 



tPolypodium vulgare, L. Common Polypody. 



tCheilanthes vestita, Swartz. Hairy Lip-Fern. Clothed Lip-Fern. 

 Great Falls; Chain Bridge. 



