ANALYTICAL KEY. 29 



Ovary really free from the calyx, but permanently invested by its 



tube, or the base of it, so as to seem inferior. 



Shrubs, with scurfy leaves : flowers mostly dioecious. EL^JAONACE^J, 424 

 Herbs : with the calyx colored like a corolla. 



Leaves opposite, simple NYCTAGINACEJE, 404 



Leaves alternate, pinnate Poterium, in ROSACE^E, 146 



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

 Stipules (ochreae) sheathing the stem at the nodes. 



Tree : the calyx none : flowers monoecious, in heads. PLATANACE^B, 446 

 Herbs : the calyx present and commonly petal-like. POLYGONACE^E, 414 

 Stipules not sheathing the stem, or none. 

 Aquatic herbs, submersed or nearly so. 



Leaves whorled and dissected : style single. CERATOPHYLLACE^E, 427 

 Leaves opposite, entire : styles 2 : ovary 4-celled. CALLHRICHACE^E, 427 

 Not aquatics, herbs. 



Ovary 10-celled : berry 10-seeded. . . . PHYTOLACCACEJE, 405 

 Ovary 3- (rarely 1 - 2-) celled : juice usually milky. EUPHOKBIACE^E, 430 

 Ovary one-celled : juice not milky. 



Style, if any, and stigma only one : leaves simple : 



no scarious bracts around the flowers. . . URTICACEJE, 440 

 Style or stigmas 2 or 3 : embryo coiled or curved. 

 Stipules not scarious ; leaves palmately cleft or 



palmately compound. . Cannabineae, in URTICACE^E, 440 

 Stipules scarious. . . Illecebrese, in CARYOPHYLLACE.E, 87 

 Stipules and scarious bracts none : stamens inserted high up 



on the tube of the calyx. Scleranthus, in CARYOPHYLLACE^B, 87 

 Stipules none : but flowers with scarious bracts. AMARANTACE^E, 4 1 1 

 Stipules and scarious bracts none . . CHENOPODIACE^:, 405 

 Shrubs or trees. 



Ovules a pair in each cell of the ovary. 



Fruit 2-celled, a double samara. Acerineae, in SAPINDACE^E, 11<J 



Fruit a 1 -celled and 1 -seeded samara or a drupe. OLEACEJE, 400 



Ovules single in each cell of the 



Three - nine-celled ovary : leaves heath-like. . EMPETRACEJS, 440 



Three-celled ovary : leaves broad. . . . RHAMNACE.E, 113 



One -two-celled ovary : styles or stigmas 2-cleft. URTICACE^, 440 



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



Anthers opening longitudinally . . . THYMELEACE^E, 424 



Anthers opening by uplifted valves. . . . LAURACE^:, 422 



IS. Flowers (monoecious or dioecious] one or both sorts in catkins. 

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



Fertile flowers in a short catkin, head, or strobile. . . URTICACE^, 440 

 Fertile flowers single or clustered : sterile ones in slender catkins. 



Leaves pinnate : fertile flowers and fruit naked. . JUGLANDACE^E, 447 

 Leaves simple : fertile flowers 1 - 3 in an involucre or cup. CUPULIFEILE, 449 



