72 ARTIFICIAL KEY TO THE FAMILIES. 



Male flowers in catkins, females in catkins or buds. 



Bracts large, entire, and connate Garrija, 385 



Bracts entire, not connate. 



Stamens under each bract 2 Willoio, 375 



Stamens 4 to 8, catkins veiy small Sweet Gale, 384 



Stamens 8 Hazle, 365 



Bracts jagged and hairy Poplar, 379 



** Flowers in company with the opening leaves. 



Twigs covered with scars of former leaves Larch, 462 



No conspicuous scars ; male flowers in catkins, and 

 females usually so. 



Stamens under each bract not more than 5 Willow, 376 



Stamens more than 5 Oak and Birch families, 



365, 370 

 ••• Floivcrs cotemporaneous toith fully developed leaves. 



Leaves simple, needle-shaped Fir-tree family, 459 



Leaves simple, lanceolate. 



Surfaces all in one plane Yeic-tree, 466 



Surfaces not in one plane Willoivs, 376 



Leaves simple, cordate, 2 to 3 inches across Mulberry, 382 



Leaves simple, fan-lobed ; lobes 5 to 7 Fig-tree, 382 



Leaves simple, minute, appressed Cupressinece, 461 



Leaves pinnate, aromatic ; flowers green Walnut, 384 



Leaves pinnate, scentless ; flowers crimson Sumach, 153 



B. — Herbaceous plants. 



1. Aquatic. 



■\Vholly submerged. 



Leaves linear, undivided Zannichellia, 411 



Leaves forked Water Horn-wort, 361 



Floating or close to the surface. 



Distinct stems and leaves Water Star-weed, 383 



Plant consisting only of horizontal green ^lates...Duchneat, 418 



2. Marsh or semi-aquatic, growing erect. 



Flowers in dense clul)s several inches long Bulrush, 413 



Flowers in globular heads Water-burr, 413 



Flowers in loose panicles, open spikes, or catkins. 



Sheath of leaves tubular Sedge family, 441 



Sheath of leaves open at the side Grass family, 421 



3. Dry land plants. 



Flowers with a large spathe and spadix Anim family, 411 



Stems usually milky -juiced ; ovary tlirce-lobed Spurge, 359 



Leaves linear, parallel-veined. 



Sheath of leaves tubular Sedge family, 441 



Sheath of leaves ojien at the side Grass family, 421 ■ 



Stems twining ; flowers in green cones Hop (female flower), 356 



