KEY. 249 



loose, flattisli, 2-oviilc(l, spreading at maturity. Leaves 

 scale-like, imbricate and appressed. 



Thuja Occident alls, L. 



78S. Leaves pinnate. Sterile flowers in aments, with an 

 irregular perianth ; fertile ones solitary or clustered. Calyx 

 of the fertile flowers 3- to 5-lobed ; its lube adherent to the 



2- to 4-celled ovary. Fruit a tryma 783 



Leaves simple, sometimes lobed, often later than 

 the flowers 784 



783. The fertile flowers with a 4-cleft calyx and no 

 corolla. Style none ; stigma divided, 2-lobed, the lobes 2- 

 cleft. Shell (epicarp) 4-valved ; nut (nucleus) nearly quad- 

 rangular, even. Sterile flowers in mostly 3-parted aments ; 

 calyx-scale 3 parted ; stamens 4-6 ; anthers hairy. Carya. 



The fertile flowers with a 4-cleft calyx and a 4- 

 parted corolla ; stigmas 2. Epicarp indehiscent ; nut rugose 

 and irregularly furrowed. The sterile flowers in simple 

 aments ; calyx-scale 5- or G-parted, somewhat bracteate at 

 the base; stamens about 20. Juglans. 



784. Flowers in terminal racemes, or else umbellate- 

 corymbed, or clustered, monoecious by abortion. Stamens 

 mostly 8, or S-G. The 2-styled ovary 2-lobed. Fruit a 

 double samara. Leaves palmately lobed. (16'J') Acer. 



Flowers all axillary, mOnceciously-polygamous. 

 Fruit nut-like, or a drupe 785 



Flowers, both sorts, or only one kind, in aments, 

 ament-like heads, or spikes 786 



785. Calyx bell-shaped, 4- to 5-cleft; stamens 4 or 5 ; 

 stigmas 2, oblong. Fruit nut-like, indehiscent, roughened 

 with scale-like jDoints. Flowers in clusters of 2-5. 



(663) Planer a aquatica, Gmel. 

 Calyx of the sterile flowers 6-parted ; stamens 6 ; 

 that of the fertile or perfect ones 5-parted, mostly with (5) 

 stamens; stigmas 2, subulate, recurved. Drupe globular, 1- 

 seeded, as large as a bird-cherry. Flowers solitary or clus- 

 tered. (663) Celtis. 



786. Only one sort of flowers in aments, or ament-like 

 heads. Fertile flowers solitary, or few together, bud-like. 



787 



