336 



IOWA ACADEMY OF SCIENCE Vol. XXV, 191S 



pubescent. Fourth leaf similar, reddish pubescent above and be- 

 low ; young bud reddish. Trichomes pointed, one-celled, slender, 

 straight or curved at end; wall of medium thickness, basal por- 

 tion enlarged ; cell contents slig^htly colored. 



CORNACE.^ 



Lubbock^*^ describes seedlings of Aucuha japonica Thunb. 



Cornus alternifolia- (Tourn) L. Do^^wood. Seeds collected in 

 fall of 1917. Stratified out of doors in humus soil, planted in 



Fig. 116 



Fi-g. 115. — Germination of Dogw'ood (Coi-nus alternifolia), showing radicle, 

 caulicle, the cotyledons and the opposite entire leaves. Photographed by 

 Photo Section, F. E. Colburn. 



Fig. 116. — Germinating green ash (Fraxinus pennsylvanica var. lanceolatd) . 

 The right hand figure shows seeds attached, cotyledons sessile, erect, first 

 leaves simple, alternate. Photographed by Photo. Section, F. E. Colburn. 



greenhouse March 14, germinated April 15, 1918. Germination 

 epigrasous; hypoeotyl purplis'h; cotyledons elliptical, fleshy, 

 smooth, size 3 mm. to 7 mm. by 10 mm. to 15mm., upper surface 

 with scattered hairs. First pair of leaves opposite, l)roadly ovate, 



^''A contribution to our knowledge of seedlings, 2, p. 45. 



