KEY. 249 



loose, flattish, 2-ovuled, spreading at maturity. Leaves 

 scale-like, imbricate and appressed. 



Thuja occidentalis, L. 



783. 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 tube adherent to the 



2t to ■1-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. Oarya. 



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 6-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 3-6. The 2-styled ovary 2-lobed. Fruit a 

 double samara. Leaves palmately lobed. (167) Acer. 



Flowers all axillary, monoBciously-polygamous. 

 Fruit nut-like, or a drupe 785 



Flowei-s, both sorts, or only one kind, in aments, 

 ament-likc 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 points. Flowers in clusters of 2-5. 



(663) Flanera 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. 



78G. Only one sort of flowers in aments, or ament-like 

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



787 



