A KEY, BASED MAINLY UPON THE FLOWERS, 



Designed as an Aid in the Identification of the Species represented in 

 Parts I, H, in and IV. 



a. Angiospermae seeds in a closed ovary. 

 b. Polypetalous petals present and distinct. 

 c. Stamens numerous, more than 10, and 



d>. Calyx iDferior wholly free from the pistil or pistils. 

 e. Pistils numerous and cohering in a cone-like mass. (MagnoliacicB). 

 /. Anthers opening inward; leaves folded lengthwise in the bud (Mag- 

 nolia}, pointed at both ends and 



Thick, glauceous beneath 51. M. GLAUCA. 



Thin, green beneath 1. M. ACUMINATA. 



/ 2 . Anthers opening outward and leaves folded crosswise in the bud. 



2. LlRIODENDRON TULIPIFERA. 



e 2 . Pistils more than one, separate (or nearly so) stamens inserted on re 

 ceptacle and filaments shorter than anthers (Anonacece). 



76. ASIMINA TRILOBA. 



e 3 . Pistil solitary and 

 /. One-celled, style single, flowers perfect, stone of drupe bony (Prunus) 



and 

 g. Compressed, with ridged margin; calyx-lobes glandular serrate. 



81. P. NIGRA. 



0r 9 . Marginless; flowers in 



h. Racemes terminal 29. P. SEROTINA. 



h*. Corembose umbels 55. P. PENNSYLVANICUM. 



7i 3 . Umbels; leaves 



Acuminate, hairy beneath 56. P. AVIUM. 



Acute, nearly smooth beneath 82. P. CERASUS. 



/*. Compound as shown by the styles and cells of ovary, calyx valvate 

 in the bud, deciduous (Tiliacece); stamens somewhat polydelphous 

 (Tilia) and with 5 petal-like scales opposite the petals. 



3. T. AMERICANA. 



(V. Calyx superior adnate to the ovary or at least its lower half; ovules. 

 e. More than one in each cell; ovary. 

 /. 2-5 celled; fruit a, 



ff. Pome with 2-5 papery carpels (Pyrus); leaves. 

 h. Simple and styles. 



