GENEEAL KEY. iii 



Shrubs with scurfy leaves; flowers mostly dioecious. 



Elaeagnaceae in THYMELEALES 229 



Herbs, with the calyx colored like a corolla. 

 Leaves opposite, simple. 



Nyctaginaceae in CHENOPODIALES 132 



Leaves alternate, pinnate Sanguisorba in EOSALES 178 



Ovary plainly free from the calyx, which is sometimes wanting. 

 Stipules sheathing the stem at the nodes. 



Trees, calyx none; flowers monoecious, in heads. 



Platanaceae in EOSALES 167 

 Herbs; calyx present and commonly petal-like. 



' ' POLYGONALES 128 



Stipules not sheathing the stem, or none. 

 Aquatic herbs, submerged or nearly so. 



Leaves whorled and dissected; style single. 



Ceratophyllaceae in EANALES 143 

 Leaves opposite, entire; styles 2; ovary 4-celled. 



Haloragidaceae in MYETALES 230 

 Not aquatic herbs. 



Ovary lO-celled; berry 10-seeded. 



Phytolaccaceae in CHENOPODIALES 132 

 Ovary 3- (rarely 1-2) celled; juice usually milky. 



Euphorbiace.^e in GEEANIALES 20.5 

 Ovary 1-celled; juice not milky. 



Style, if any, and stigma only 1; leaves simple; no 



searious bracts around the flowers. . .UETICALES 124 

 Styles or stigmas 2 or 3 ; embryo coiled or curved. 

 Stipules not searious; leaves palmately cleft or 

 palmately compound. 



Cannabis and Humulus in UETICALES 126 

 Stipules searious or none . . . CHENOPODIALES 132 

 Shrubs or trees. 



Ovules, a pair in each cell of the ovary. 

 Fruit 2-oelled, a double samara. 



Aceraceae in SAPINDALES 214 

 Fruit a 1-celled and 1-seeded samara or a drupe. 



Oleaceae in GENTIANALES 2.53 

 Ovules single, in each cell of the 



Three-9-celled ovary; leaves heath-like. 



Empetraceae in SAPINDALES 214 

 Three-celled ovary; leaves bread. 



Ehamnaceae in EHAMNALES 218 

 One-2-celled ovary; styles or stigmas 2-cleft. 



UETICALES 124 

 One-celled ovary; style and stigma single and entire. 

 Anthers opening longitudinally. 



Thymeleaceae in THYMELEALES 22f» 

 Anthers opening by uplifted valves. 



' Lauraceae in EANALES 143 



B. Floivers monoecious or dioecious, one or both sorts iii catkins. 



1. Only one sort of flowers in catkins or catkin-like heads. 



Fertile flowers in a short catkin, head or strobile UETICALES 124 



Fertile flowers single or clustered; sterile in slender catkins (except 

 Fagus). 

 Leaves pinnate; fertile flowers and fruit naked. .JUGLANDALES 118 

 Leaves simple; fertile flowers 1-3 in an involucre or cup. 



FAG ALES 119 



2. Both sterile and fertile flowers in catkins or catkin-like heads. 

 Ovary and pod 2-celled, many-seeded Liquidambar in EOSALES 171 



