FLORA 07 THE DISTRICT OP COLUMBIA. 45
S. SOBGHASTBTJM
I. CYPEBUS L
1. SAURTJSUS L
1. Saururus ceniuus L. Lizard's-tail.
Swamps and shallow water; common. June-Aug. Eastern U. S.
A rather showy tall plant with heart-shaped leaves and long slender recurved spikes of small white flowers. It has a ginger-like odor. A characteristic colony of
plants is shown in plate 21.
34, SALICACEAE. Willow Family.
Bracts of the catkins entire or obscurely toothed; stamens few (1-10); stigmas short;
bud scale 1; leaves much longer than broad 1. 8ALU.
Bracts deeply and sharply toothed; stamens numerous; stigmas elongate; bud scales several; leaves broad, often as broad as long 2. POPULUS.
1. SALZX L. Willow.
The following species are often cultivated, and isolated individuals may be found in waste places: Salix purpurea L., S. pentandra L., and 5. caprea L.
KEY TO SPECIMENS WITH CATKINS.
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Catkins stalked, appearing with the leaves or after them; capsule glabrous (hairy when young in S. interior).
Catkins appearing long after the leaves, often clustered, terminating long leafy twigs. Leaves linear or broadly linear, remotely and minutely toothed, green on both sides, more or less hairy when young; stamens 2; shrub.
1. S. Interior.
Catkins appearing with the loaves, solitary, terminating short leafy stalks.
Scales of the catkins brown, at least at the tip, persistent; filaments glabrous.
Catkins nearly sessile; leaves lanceolate or broadly lanceolate, closely serrate, glabrous, pale beneath; shrub 7. S. cordata.
Scales pale yellow, deciduous; filaments hairy.
Stamens 3-7; pedicels 1-3 mm. long; shrubs or small trees.
Leaves narrowly lanceolate, green on both sides 2. S. nigra.
Leaves broader, glaucous beneath i 3. S. wardi.
Stamens 2; pedicels less than X mm. long; trees. Leaves lanceolate, glaucous beneath.
Twigs long, pendulous, tougb. Capsule nearly sesaile; leaves linear-lanceo- late, glabrous, minutely serrate 6. S. babylonica.
Twigs short, not pendulous, fragile at the base.
Capsule short-pediceled; leaves glabrous or nearly so, coarsely serrate;
petioles glandular 4. S. fragilis, Capsule sessile; leaves usually silky, even in age, finely serrate; petioles
scarcely glandular. 5. S. alba.
FLORA OF THE DISTRICT OF COLUMBIA. 133
Catkins sessile, appearing before the leaves; capsule pubescent or woolly. Scales of the catkins black, long-hairy.
Catkins slender; capsule 3-4 mm. long, silvery-pubescent; leaves silvery-silky and glaucous beneath; treelike shrub 8. S. sericea.
Catkins stout; capsule 6-8 mm. long, woolly; leaves oblanceolate, woolly beneath;
low shrubs.
Catkins oval-oblong, 1-3 cm. long; leaves broadly oblanceolate, 5-8 cm. long;
shrub 1 meter high or more *. 9. S. humilis.
Catkins nearly spherical, 0.5-1.5 cm. long; leaves narrowly oblanceolate, 2-5 cm. long; shrub about 0.5 meter high 10. S. tristis.
KEY TO SPECIMENS WITH LEAVES ONLY.
Leaves glabrous when fully grown.
Leaves green on both sides.
Leaves linear or broadly linear, remotely and minutely toothed.. .1.8. interior.
Leaves narrowly lanceolate, closely serrate 2. S. nigra.
Leaves pale or glaucous beneath.
Twigs long, slender, pendulous; leaves linear-lanceolate, minutely serrate.
6. S. babylonica.
Twigs short, not pendulous; leaves lanceolate.
Stipules very small, inconspicuous, early deciduous.
Petioles glandular; leaves coarsely serrate 4. S. fragilis.
Petioles usually without glands; leaves finely serrate 5. S. alba.
Stipules large, conspicuous, usually persistent, especially on young shoots.
Leaves narrowly lanceolate, very glaucous beneath 3. S. wardi.
Leaves broadly lanceolate, slightly glaucous beneath 7. S. cordata.
Leaves hairy when fully grown.
Leaves silvery-silky beneath or on both sides.
Leaves linear or broadly linear, remotely and minutely serrate 1. S. interior.
Leaves lanceolate, closely serrate.
Twigs fragile; leaves tliinly or closely silky on both sides; introduced tree.
S. S. alba.
Twigs not fragile; leaves thinly silky beneath; native shrub 8. S. sericea.
Leaves gray-tomentose, especially beneath.
Leaves broadly oblanceolate, 5-8 cm. long 9. S. humilis.
Leaves narrowly oblanceolate, 3-5 cm. long 10. S. tristis.
1. Salix interior Rowlee. Sandbar willow.
Along the upper Potomac. Apr -May. Eastern N. Amer. (S. longifolia Muhl.) 2. Salix nigra Marsh. Black willow.
Along streams; common. Apr.-May. Widely distributed in N. Amer. (S.
nigra falcuta Torr.)
A hybrid between thia and S. wardi hag been found along the canal near High Island.
8. Salix wardi Bebb. Wabd'b willow.
Rocky banks and flats along the upper Potomac; common. Apr.-May. Southern states, north to Md. (S. nigra wardi Bebb.)
The species was described from specimens obtained by Ward near Chain Bridge.
4. Salix fragilis L. Crack willow.
Along the Eastern Branch, Fourmile Run, and Hunting Creek. Apr.-May.
Native of Eur.; often cultivated and becoming naturalized in eastern N. Amer.
5. Salix alba L. White willow.
Established in a few places along streams. Apr.-May. Native of Eur.; culti- vated or naturalize eastern N. Amer.
6. Salix babylonica L. Weeping willow.
Along the upper Potomac; infrequent. Apr,-May. Native of Asia; cultivated and naturalized in eastern N. Amer.
7. Salix cordata Muhl.
Along the Potomac, Eastern Branch, and Hunting Creek. Apr.-May. Widely distributed in N. Amfer.
A hybrid between this and S, sericea is found occasionally.
8. Salix sericea Marsh. Silky willow.
Along streams; common. Apr.-May. Eastern N. Amer.
9. Salix lumilis Marsh. Prairie willow.
Dry fields, thickets, and open woods; frequent. March-Apr. Eastern N. Amer.
10. Salix tristis Ait. Dwauf praijue willow.
Dry fields and woods, chiefly eastward. Apr.-May. Eastern N. Amer.
2. POPFLUS L. Poplar.
Leaves deltoid or cordate-delt oid, glabrous on the surfaces, eilialc; buds glabrous, resi- nous; floral bracts fulling early 1. p. virgin iana- Leaves rounded, oval, or cordate-oval; buds neither glabrous nor resinous; lioral
bracts persistent.
Leaves on ihc young branches cordate-ovate, 15-20 cm. long or more.
Leaves eremite, long-petioled, auriculate at base, the auricles overlapping.
5. P. heterophylla.
Loaves dentate or denticulate, the normal leaves broadly oval, acule, 5-10 cm.
long, sericeous at first, glabrous in age 2. P. grandidentata.
Leaves on I he young 1 ranches broadly cordato-ovale, rarely over H) cm. long, irreg- ularly toothed or lobed.
Leaves on the young branches deeply 5-lol-od, dark-green above, "white-woolly beneath; normal leaves with more or le.ss persistent, wool; petioles thor'er ihan the blades 3. P. alba.
Leaves on the young I ranches irregularly toothed, not. deeply lobed, .silvery- caiHSflconr. or woolly; normal leaves commonly ovate, acute, canuscent.,
becoming glanrous; petioles equaling or exceeding the blades.
4. P. eaiiesecns.
1. Populus virginiana Fouger. Cottok wood.
River bottoms and low places. Apr. Middle Atlantic states. (P. irinnilifera Ait.) Popuhis italica Moench (I', dilatata Ait.; P. niyra it alien DuKoiV the Lombardy poplar, is extensively planted; readily recognized by its very broad, deltoid, abruptly acuminate root-shoot leaves and erect fastigiate branches. Native of Eur.
Populus nigra L.. the black poplar, is occasionally planted. Native of Eur. The normal leaves are rhombic-acuminate. 5-8 cm. long, the branches spreading and in age horizontal.
Popubts eugenci Simon-Louis (P. vwnilifcra. of authors, not Ait.), the Carolina poplar, is extensively planted in our streets and parks. It has an excurrent trunk and spreading branches; the leaves are triangular-ovate, broadest below the middle, long- acuminate. those of the root shoots more or less deltoid, tho teeth in both cases being incurved.
2. Populus grandidentata Miehx. Large-toothed aspen.
Deciduous woods. Apr. Northern states, south to M. C.
Populus Iremuloides Michx., the American aspen, has escaped from cultivation near Chevy Chase Lake (Maxon Standley). Can. to Pa. and Nobr. Readily recognized by its broadly ovate or orbicular, crenulato, abruptly acuminate leaves, cm, long.
FLORA OP THE DISTRICT OF COLUMBIA. 135
3. Popnlus alba L. White or silver poplar.
Abandoned nurseries and old fields. March. Native of Eur. and Asia.
Populus alba bolkana Masters, Bolle's poplar, from Turkestan, is distinguished from the species by its pyramidal form and fastigiate branches. The leaves are larger and more deeply lobed than in the type and the lobes are incisely toothed.
4. Popnlus canescens (Ait.) J. E. Smith. Gray poplar.
In cultivation and escaped. March. Native of Eur.
Populus tacamahaca Mill. (P. carulicans Ait,; P. balsamifera candicans A. Gray), the Balm of Gilead, is cultivated. Native of northern U. S. It is recognized by its broadly ovate, crenulate leaves, 6-20 cm. long, silvery beneath.
0. Populus heterophylla L. Swamp poplar.
Low ground and swamps; above Great Falls (Bartlett). Apr. Eastern states, south to Ga.
35. MYRICACEAE. Bayberry Family.
Leaves entire or toothed, without stipules; fruit a small drupe, usually covered with wax 1. MYRICA.
Leaves pinnately lobed, with stipules; fruit nutlike, surrounded by a burlike invo- lucre 2. COMPTONIA.