PHILOSOPHICAL SOCIETY OF WASHINGTON. 83 



Salix tristis, March 17, 1877. 

 Populus grandidentata, March 21, 1880. 

 Corydalis flavula, March 22, 1874. 

 Thalictrum anemonoides, March 24, 1878. 

 Dentaria laciniata, March 24, 1878. 

 Antennaria plantaginifolia, March 24, 1878. 

 Erodiuin cicutarium, March 27, 1874. 

 Erigenia bulbosa, March 28, 1875. 

 Cardamine hirsuta, March 30, 1879. 



It is about the first of April, especially in early years, that the 

 vegetation seems to receive the greatest impetus. This is well shown 

 by the following list of species seen in flower during the first week 

 in April : 



Ulmus Americana, April 1, 1873. 



JefFersonia diphylla, April 2, 1876. 



Cardamine rhomboidea, April 2, 1876. 



Stellaria pubera, April 2, 1876. 



Thaspium aureum, April 2, 1876. 



Euphorbia commutata, April 2, 1876. 



Alnus serrulata, April 3, 1881. 



Ranunculus abortivus, April 4, 1880. 



Dicentra Cucullaria, April 4, 1880. 



Arabis laevigata, April 4, 1880. 



Viola tricolor, var. arvensis, April 4, 1880. 



Vicia Caroliniana, April 4, 1880. 



Amelanchier Canadensis, April 4, 1880. 



Nepeta Glechoma, April 4, 1880. 



Sassafras officinale, April 4, 1880. 



Carpinus Americana, April 4, 1880. 



Ostrya Virginica, April 4, 1880. 



Erythroneum Americanum, April 4, 1880. 



Barbarea vulgaris, April 5, 1874. 



Pedicularis Canadensis, April 5, 1874. 



Mertensia Virginica, April 5, 1874. 



Ranunculus abortivus, var. micranthus, April 7, 1878. 



Ranunculus repens, April 7, 1878. 



Asimina triloba, April 7, 1878. 



Caulophyllum thalictroides, April 7, 1878. 



Arabis dentata, April 7, 1878. 



