ANALYTICAL KEY 13 



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



Parasitic on 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 PLATAN AC EAE, 454 



Leaves ovate or oblong, entire LEITNEBIACEAE, 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 MYBICACEAE, 329 



Y. Flowers not in catkins 6. 



6. 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. 



Calyx present, usually colored or petal-like RANUNCULACEAE, 392 

 Calyx none ; flowers spiked PIPERACEAE, 320 



c. 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. 



i. Leaves palmately lobed or divided Cannabineae, 344 



i. 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 l-oo , 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 3-angled achene Eriogonum, 353 



k. Flowers not involucrate. 



Leaves covered at least beneath with stel- 

 late hairs ; embryo straight EUPHORBIACEAE, 540 



