KEY TO XATURAL OEDERS. 23 



B. Flo"ut:rs, o^te or both sorts, ix amexts or catki:s like heads. 



Twining dioecious herbs ; fertile flowers onlv in p^gh 

 short aments. Humulus in Urtica;;e^, 291 



Shnibbv plants, parasitic on trees. Fruit a berry. Loraxthace^ 286 



Trees or shrubs. 



Sterile flovrers only in aments. Plowers 

 monoecious. 



Leaves pinnate. Ovaiy and fruit -u-ith- 



out an involucre. Juglaxtdacej:, 302 



Leaves simple. Xuts one or more in a 



cup or involucre. Cupulifer^ 307 



Flowers of both kinds in aments or close 

 heads. 



Leaves palmately-veined or lobed. 



Calyx 4-cleft, in the fertile flowers 



becoming berry-like. 3*Iorus in L^rticace^. 291 

 Calyx none : flowers in round heads. Plataxacej:, 301 

 Leaves pinnately-veined. 



Flowers dioecious. 1 on each scale. 



Pod many-seeded. Salicace-E, 328 



Flowers monoecious, the fertile ones 



2 or more under each scale. Betulace^, c24 



Flowers only 1 under each fertile 

 scale. 



Fruit 1 -seeded. Mtricace-E, 323 



Sub-class 2. G-tmxosperms. Pistil represented by an open scale or leaf 

 or sometimes entirely wanting ; the ovules and seeds naked. 

 Flowers monoecious or dioecious. Stems 



branched. Leaves simple. C0NIFEE.B, 833 



