338 SALICACEAE 



with a nearly white bark : leaf -blades leathery, oblong-obovate, elliptic-obovate, or some- 

 times spatulate, 4-8 cm. long, obtuse, usually entire, lustrous above, bright green beneath ; 

 petioles short, partially winged: staminate" aments stout, 1-1.5 mm. long, their bracts 

 orbicular-ovate, about as broad as high : pistillate aments elongated, slender, their bracts 

 loosely imbricated, orbicular-ovate, broader than long : fruits globose, 5-7 mm. in diam- 

 eter, often solitary: seeds oblong or oblong-ovoid. [Myrica inodora Bartr.] 



About pine-land ponds and swamps, near the coast, Florida. Flowers during February and March. 



Order 6. SALICALES. 



Dioecious shrubs or trees, with soft weak wood and bitter bark. Leaves 

 alternate, with or without stipules : blades simple, entire or toothed : inflores- 

 cence consisting of bracted aments. Flowers solitary in the axils of the bracts. 

 Perianth (?) a gland or a cup-shaped disk. Staminate flowers of 2 or more sta- 

 mens : anthers introrse, innate. Pistillate flowers similarly disposed. Gynoecium 

 of 2 or rarely 4 united carpels. Ovary 1-celled with 24 parietal placentae : 

 stigmas 2-4, more or less divided and sometimes raised on a short style. Ovules 

 numerous. Fruit a dehiscent capsule. Seeds numerous, each bearing a coma. 

 Endosperm wanting. Embryo straight. 



FAMILY 1. SALICACEAE Lindl. 1 WILLOW FAMILY. 

 Characters of the order. 



Bracts incised : disk cup-shaped : stamens usually 10 or more, or rarely 7 or 8 : stigmas 



elongated and expanded : winter-buds with several scales. 1. POPULUS. 



Bracts entire : disk reduced to 1 or more axillary glands : stamens less than 10 : stigmas 



short, not expanded : winter-buds with one scale each. 2. SALIX. 



1. POPULUS L. 



Large trees, with furrowed bark and stout twigs terminated by scaly, often resinous 

 buds. Leaf-blades palmately veined, usually coarsely toothed, or lobed ; the relatively ' 

 long petioles, sometimes laterally flattened, subtended by membranous, caducous stip- 

 ules. Flowers in drooping lateral aments, adapted to anemophilous pollination : bracts 

 membranous, lobed or fimbriate at the apex, usually caducous : disk cup-shaped, often 

 oblique, entire, toothed or irregularly lobed, adnate to the pedicel of the flower. Stamens 

 adnate to the disk : filaments distinct, glabrous : anthers purple or red. Ovary sessile in 

 the disk, glabrous, or rarely villous : style short: stigmas dilated. Ovules anatropous. 

 Capsule opening by 2-4 recurved valves. The plants flower in the spring and mature their 

 fruit in the summer. 



Petioles much flattened laterally. 

 Leaf-blades ovate or suborbicular. 



Leaf-blades crenate-dentate : bracts usually surpassing the pistils. 1. P. tremuloides. 



Leaf-blades sinuate-dentate : bracts usually shorter than the pistils. 2. P. grandidentata. 



Leaf-blades deltoid or somewhat renif orm. 



Stamens 6-8 : branches erect. 3. P. dilatata, 



Stamens 50 or more : branches spreading. 



Leaf-blades mostly longer than broad : disk very small and inconspicuous. 4. P. deltoides. 

 Leaf-blades mostly broader than long : disk large, usually conspicuous. 

 Leaf-blades truncate and slightly cordate at the base, with many 



relatively small teeth : pedicels mostly less than 4 mm. long. 5. P. Frcmontii. 



Leaf-blades more or less cuneately narrowed on the petiole, with few 



relatively large teeth : pedicels mostly over 5 mm. long. 6. P. Wislizeni. 



Petioles terete or channeled. 



Leaf-blades glabrous or nearly so when mature, not lobed. 



Stigmas dilated : leaf-blades acuminate : anthers about as broad as long : 



capsules less than 1 cm. long. 7. P. candicans. 



Stigmas narrow : leaf-blades blunt : anthers about twice as long as broad : 



capsules over 1 cm. long. 8. P. heterophylla. 



Leaf-blades persistently white-tomentose beneath, 3-5-lobed. 9. P. alba. 



1. Populus tremuloides Michx. A slender tree, reaching a maximum height of 

 about 30 m. and a trunk diameter of 1 m., with glabrous foliage, except the ciliate margins 



Prepared with the assistance of Dr. W. W. Rowlee. 



