512 FLORA OF TEXAS. 



with the roundish bracts transversely ridged on the back; 

 stamens about 10, monadelphous ; fertile aments small, 

 elongated in fruit; stigmas 2 or 4; scales of the ovary 5 ; 

 nuts large, black, commonly solitary. Margins of pine- 

 barren ponds and swamps. February-March. — A shriib or 

 small tree, with whitish bark ; leaves about 2' long, spar- 

 ingly dotted ; nuts ovoid, 3" long. 



122. BIRCH FAMILY. Order, Betulace^. 



Trees or shrubs, with alternate simple straight-veined 

 leaves, deciduous stipules, and monoecious amentaceous 

 ^0i(?er5, placed 2-3 together in the axil of a 3-lobed bract; 

 stamens 4 ; filaments distinct ; ovary 2-celled, with a single 

 suspended anatropous ovule in each cell; stigmas 2, elon- 

 gated ; fruit a winged or angled 1-celled 1-seeded nut, 

 forming, with the imbricated persistent bracts, a cone-like 

 spike. 



BETULA, Tourn. Birch. 



Sterile aments drooping; tracts 3-flowered, 2-bracteolate, 

 peltate; calyx scale-like; stamens short; anthers 1-celled; 

 fertile aments oblong or cylindrical; hracts 3-flowered; 

 calyx none; stigmas filiform; nut broadly winged ; coty- 

 ledons oblong. — Trees or shrubs, with the outer bark often 

 separable into thin papery sheets ; leaves petioled, serrate ; 

 fruiting bracts membranaceous. 



B. nigra, L. {Blach Birch) Leaves rhombic-ovate, 

 acute, doubly serrate, smooth above, hoary-tomentose be- 

 neath, like the short petioles. and branchlets, becoming 

 rusty or smoothish ; sterile aments long and drooping; the 

 fertile ones oblong, short-peduncled, with the woolly bracts 

 cleft into three linear-oblong nearly equal lobes. (B. rubra, 

 Michx.) Banks of rivers. March.— A middle-sized tree, 

 with reddish-broAvn bark, and long spreading branches. 



