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IOWA ACADEMY OF SCIENCE VoL. XXVII, 1920 
Fig. 10a. Populus deltoides Marsh. Cottonwood seedling, showing cotyledons and 
four subsequent pairs of leaves. Drawn by C. M. King 
Fig. 10b. Ulmus racemosa Thomas. Cork elm. Seedling showing cotyledons and 
first pair of leaves. Drawn by C. M. King 
Fig. lO'c. Berberis macracantha (“No. 7” from Sargent, Arnold Arboretum) Bar- 
berry. Seedling showing cotyledons and first pair of leaves. Drawn by C. M. King 
Fig. lOd. Berberis laxidora oblanceolata (“No. 22,” from Sargent). Seedlings, 
showing cotyledons and first and second pair of leaves. Drawn by C. M. King 
Fig. lOe. Citrus Decumana I/. Grape fruit. Seedling showing the two large 
cotyledons and two subsequent pairs of leaves. Drawn by C. M. King 
Fig. lOf. Ampelopsis heterophylla. Blume. Woodbine. Seedling showing cotyle- 
dons Drawn by C. M. King 
