454 CASUABTNACE.E. 



2. POPULUS, Tourn. COTTONWOOD, POPLAR, ASPEN. 



Bracts of the ameuts toothed or lobed. Flowers from an oblique cup-shaped 

 disk. Stamens few or numerous, with the filaments free. Stigmas elongated, 

 2-parted. Trees. Leaves ovate or roundish, on long and often laterally 

 compressed petioles. Buds covered with imbricated, often resinous-coated 

 scales. Aments slender, drooping, appearing before the leaves. 



1. P. angulata, Ait. Branches thick, smooth, and sharply angled; 

 leaves large, smooth, deltoid-ovate, acute- or slightly acuminate, truncate at 

 the base, obtuselv serrate with incurved teeth ; the conspicuous veins and 

 compressed petiole yellowish. Banks of rivers. March- April. A large 

 tree. Leaves 6' -8' long, longer than the petiole. 



2. P. grandidentata, Michx. Branches terete; leaves round-ovate, 

 acute, sinuate-toothed, hoary -tomentose when young, like the brauchlets, at 

 length smooth, scarcely longer than the slender compressed petiole; fruiting 

 ameuts elongated, pubescent. Low woods in the upper districts. March - 

 April. A middle-sized tree, with smooth gray bark. Leaves 3' - 5' long, 

 and nearly of the same width. 



3. P. heterophylla, L. Branches terete ; leaves ovate, mostly obtuse, 

 serrate, with obtuse, incurved teeth, rounded or with a small sinus at the base, 

 hoary-tomentose on both sides when young, like the nearly terete petioles and 

 branchlets, at length only on the veins beneath ; fruiting aments smooth. 

 River swamps in the middle and upper districts. March -April. A large 

 tree. Leaves 3' -5' long. 



& 



4. P monilifera, Ait. Branchless obtusely angular; leaves deltoid- 

 ovate, acuminate, serrate (3'- 10' long) ; fertile aments long and slender; 

 stigma large, toothed ; capsule oblong ovate. River banks, Florida, and 

 northward. A large tree. 



ORDER 133. CASUARINACE^S. 



Trees or shrubs, with leafless jointed furrowed branches, like Equi- 

 setum. Flowers in spikes, monoecious or dioecious, the staminate ones 

 in whorls at the joints, monandrous, 4-bracted, the pistillate flowers 

 capitate, without floral envelopes. Ovary 1 -celled, with 1-2 or- 

 thotropous ovules, forming in fruit a winged achenium. Styles 2. 

 Albumen none. Radicle superior. 



1. CASUARINA, Rumph. 

 Characters of the Order. 



1. C. equisetifolia, Forst. Branches filiform, simple; furrows 6-8; 



teeth of the sheaths as many, keeled on the back ; staminate spike terminal, 

 the pistillate lateral, short-peduncled. Keys of South Florida 



