96 MIDDLESEX FLORA. 



POPULUS, Tourn. 



P. tremuloides, Michx. American Aspen. 



Common. Found with polygamous flowers, Medford, 187S (G. E. 



Davenport). Apr. 

 P. grand identata, Michx. Large-toothed Aspen. 



Common. Apr. 

 P. balsamifera, L., var. candicans, Gray. Balm of Gilead. 



Common. Possibly introduced from farther North. May. 

 P. dilatata, Ait. Lombardy Poplar. 



Formerly extensively cultivated, and occasionally spontaneous, 



but apparently dying out. Adv. from Eu. 

 P. ALBA, L. Abele. White-Poplar. 



Occasional; spreading extensively by root. Nat. from Eu. 



CONIFER/E. PINE FAMILY. 



PiNUS, Tourn. 



P. rigida, Mill. Pitch Pine. 



Common. May. 

 P. resinosa, Ait. Norway Pine. Red Pine. 



Generally distributed, but not common. May. 

 P. Strobus, L. White Pine, 



Common. June. 



PiCEA, Link. 



P. nigra, Link. (Abies nigra of Man.) Black Spruce. 

 Kather scarce, especially eastwai'd. May. 



TsuGA, Endl. 



T. Canadensis, Carriere. (Abies Canadensis, Michx., Man.) 

 Hemlock. 

 Rather common. June. 



Abies, Tourn. 



A. balsamea, Marsh. Fir Balsam. 

 Ashby, near Mt. Watatic (Dr. C. W. Swan) ; Concord, introduced 

 by Minot Pratt). Pare. May. 



Larix, Tourn. 



L. Americana, Michx. American Larch. Black L. Tama- 

 rack. IIackmatac. 

 Widely distributed; not uncommon. Apr.-May. 



