THE GERMINATION OF SOME TREES AND SHRUBS 
AND THEIR JUVENILE FORMS* 
L H. PAMMEL AND C. M. KING 
In our studies of seedlings during the year 1918-1919 there have 
been included representatives of the following families : Sal- 
icace«, Urticace^, Berber idaceae, Leguminosae, Rutacese, Vitaceae, 
Cornaceae, Sapotaceae and Oleacese. 
SAMGArES 
Salicaceae 
Populus deltoides Marsh. Cottonwood. See figure 10, A. 
Seeds of the cottonwood were flying May 27, 1919. On Au- 
gust 15, 1918, on the borders of the lake upon the Iowa State 
College campus seedlings were abundantly growing, with five to 
ten leaves. 
Cotyledons still remaining on the seedling, one centimeter in 
length, one-half centimeter in width; petiolate, smooth; in shape 
ovate, with cordate base. Rootlets fibrous, abundant. Stem 
smooth, reddish. First leaves smooth, ovate, lanceolate, nearly 
entire, petiole short. Succeeding leaves increasing in length and 
width; fourth and fifth leaves ovate, at base obtuse angled, apex 
acute angled, pinnately veined, crenate margin; petiole of fourth' 
and fifth leaves longer than first to third. Later leaves approach- 
ing deltoid in shape. 
Urticaees 
Urticaceae 
Ulmus racemosa Thomas. Cork elm. See figure 10, B. 
Seeds of this elm were freely falling May 30, 1919, at the 
Ledges, Boone county. Collections that were made and planted 
at this time in the greenhouse germinated June 15, 1919. 
Germination epigaeous, the seed coat often being brought to 
the surface as the seedling grows. Cotyledons two, broadly oval, 
slightly pubescent above; hypocotyl pubescent. Stem above the 
cotyledons pubescent. First pair of leaves strongly pinnate veined, 
doubly serrate. Lower surface of leaf pubescent, especially on 
the veins ; stem densely glandular pubescent. 
* Contribution No. 3 on the Germination of Woody Plants. 
