ANALYTICAL KEY 13 



a. Ovary 1-2-celled ; cells 1-ovuled ; fruit 1-seeded. 



Parasitic ou trees ; fruit a berry LorAnthaceae, 351 



Trees and shrubs, not parasitic. 

 Calyx regular, in fertile flower succulent in fruit Urticaceae, 344 

 Calyx none or rudimentary and scale-like. 

 Style and stigma 1, simple. 

 Leaves palmately angled or lobed Platanaceae, 454 



Leaves ovate or oblong, entire Leitneriaceae, 330 



Styles or long stigmas 2. 

 Fertile flowers 2 or 3 at each scale of the catkin Betulaceae, 332 

 Fertile flowers single under each scale; nutlets 



naked, waxy-coated, or drupe-like Myricaceae, 329 



Y. Flowers not in catkins b. 



h. Ovary or its cells containing only 1-2 (rarely 3-4) ovules c. 

 c. Pistils more than 1, distinct or nearly so. 



Stamens inserted on the calyx : leaves with stipules Rosaceae, 454 



Stamens inserted on the receptacle. 

 Leaves punctate with transparent dots Zanthoxylum, 537 



Leaves not dotted. 

 Caly^x present, usually colored or petal-like Ranunculaceae, 392 

 Calyx none; flowers spiked Piperaceae, 320 



G. Pistil 1, simple or compound d. 

 d. Ovary free from the calyx, which is sometimes wanting e. 

 e. Stipules (ocreae) sheathing the stem at the nodes. 



Tree ; calyx none Platanaceae, 454 



Herbs; calyx present, commonly corolla-like Polygonaceae, 353 

 e. Stipules not sheathing the stem, or none /. 

 /. Herbs g. 

 g. Aquatic, submerged or nearly so. 



Leaves whorled, dissected ; style 1 Ceratophyllaceae, 389 

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



Callitrichaceae, 549 

 g. Not aquatics h. 

 h. Styles 10 ; ovary and berry 10-celled Phytolaccaceae, 374 



h. Style, if any, and stigma 1. 



Flowers unisexual ; ovary of the fertile flowers 



1-celled Urticaceae, 344 



Flowers perfect; pod 2-celled, 2-seeded Lepidium, 425 



h. Styles 2-3 or branched ; ovary 1-4-celled ^. 



i. Leaves palmately lobed or divided Cannabineae, 344 



». Leaves not palmately lobed or divided j. 

 j. Ovary and pod 3-celled ; juice usually milky. 



Flowers in basal spikes; stamens 4; fila- 

 ments thick, flattened Buxaceae, 550 

 Inflorescence various, not of basal spikes; 

 stamens 1-x , rarely 4 ; filaments not con- 

 spicuously thick EUPHORBIACEAE, 540 

 j. Ovary not 3-celled : juice not milky k. 

 k. Flowers in numerous small involucrate 



heads ; fruit a J^augled achene Eriogonum^ 353 



k. Flowers not involucrate. 



Leaves covered at least beneath with stel- 

 late hairs; embryo straight Euphorbiaceae, 540 



