86 MINNESOTA BOTANICAL STUDIES. 



From the foregoing it may be concluded that broad general- 

 izations in regard to the shape of cotyledons in plant families, 

 cannot be safely made without a considerable mass of data. 



EXPLANATION OF PLATES. 



Plate I. Seedlings in various stages of the following plants : Popu- 

 lus deltoides, Ulmus americana, Celtis occidentalis, Toxylon pomi- 

 ferum, Broussonetia papyrifera, Liriodendron tulipifera, But- 

 neria florida, Parkinsonia aculeata. 



Plate II. Seedlings in various stages of the following plants : Cercis 

 canadensis, Amorpha fruticosa, Amorpha nana, Robinia psetidaca- 

 cia, Ptelea trifoliata, Ailanthus glandulosa, Schinus molle, Celas- 

 trus scandens. 



Plate III. Seedlings in various stages of the following plants: Acer 

 negundo, Acer saccharimim, Acer glabrum, Berchemia racemosa, 

 Rhamnus purshiana, Vitis cordifolia, Parthenocissus quinquefolia, 

 Sterculia plantanifolia. 



Plate IV. Seedlings in various stages of the following plants : 

 Elceagnus ttmbellata, Eucalyptus globulus, Eucalypttis citriodora, 

 Cornus amomum, Afohrodendron carolinum, Catalpa speciosa, Te- 

 coma radicans, Cephalanthus occidentalis, Sambucus pubens. 



The amount of enlargement or reduction is indicated for each plant. 



