GERMINATION OF TREES AND SHRUBS 



321 



ular at tip. Fourth leaf slightly larger, smooth a'bove and be- 

 low, serrate ; petiole purplish, grooved oa upper side ; stipules 

 pointed, serrate, soon falling from early leaves. Seeds germi- 

 nating freely out of doors by April 10, 1917. 



Pig. SS. — European May Day Tree (Prunus padus) , showing radicle, 

 caulicle and petioled fleshy cotyledons and alternate serrate leaves. Photo- 

 graphed by Photo. Section, F. E. Colburn. 



Prunus serotina Ehrh. Wild Black Cherrv^ Seedlings taken 

 from field where they were numerous, May 22, 1918. Germina- 

 tion hypogjBOUS; the short stalked fleshy cotyledons do not 

 push up, plumule arising between the two cotyledons. Caulicle 

 short; root straight, brownish, lateral rootlets few. Stem above 

 the cotyledons light in color, fleshy. Leaves alternate. First leaf 

 prominently reticulately-veined, smooth above and below; ser- 

 iate, dentations glandular tipped. Stipules slender serrate, acu- 



