SAPINDALES. 597 



a narrow marginal wing or raised border, with a deep groove between them; styles 

 persistent, not longer than the fruit, spreading or reflexed. In damp, shaded 

 places, N. Y. and N. J. to Ohio, Mo., Tenn., Tex. and Mex. July-Sept. 



2. Callitriche palustris L. VERNAL WATER-STARWORT. WATER FENNEL. 

 (I. F. f. 2340.) Aquatic or growing in the mud; stems 5-25 cm. long. Sub- 

 merged leaves linear, I -nerved, retuse or bifid at the apex, 1-2 cm. long; emersed 

 or floating leaves obovate, obtuse, truncate or retuse at the apex, narrowed into a 

 margined petiole, dotted with stellate scales; aquatic forms occur with the leaves 

 all linear; fruit 2-bracted, 1-2 mm. long, about one-half as broad, slightly notched 

 at the apex, winged only toward the apex, or all around, separated by a deep 

 groove. Mostly in cold or running water, apparently occurring nearly throughout 

 the U. S. and Canada. Also in S. Am., Europe and Asia. July Sept. 



3. Callitriche heterophylla Pursh. LARGER WATER-STARWORT. (I. F. f. 

 2341.) Similar to the preceding. Fruit smaller, usually slightly less than I mm. 

 long, and about the same breadth, broadly notched at the apex, thick, almost ven- 

 tricose at the base; lobes obtusely angled with a small intervening groove, wing- 

 less, or with a narrow wing or raised border on the margins. In ponds and slow 

 streams, N. Eng. to Fla., N. W. Terr., Colo, and La. July-Sept. 



4. Callitriche bifida(L.) Morong. AUTUMNAL OR 'NORTHERN WATER-STAJI- 

 WORT. (I. F. f. 2342.) Submerged. Leaves linear or linear-lanceolate, clasping 

 at the base, retuse or bifid at the apex, i-nerved, 1-1.6 cm. long, without stellate 

 scales ; fruit sessile, or rarely minutely pedunculate, orbicular or slightly narrower 

 than long; 1-2 mm. in diameter, its lobes separated by a deep groove and broadly 

 winged on the margins; styles as long as the fruit, or shorter, soon deciduous. In 

 flowing water, Quebec to Manitoba and Ore., south in the Rocky Mts. to Colo. Also 

 in Europe and Asia. July-Sept. 



Order 20. SAPINDALES. 



Mostly trees or shrubs {Limnanthaceae and Balsamtnaceae herbs). 

 Petals usually present and separate. Sepals mostly distinct. Stamens 

 rarely more than twice as many as the sepals, when as many or fewer, 

 opposite them. Ovary superior, compound. Ovules pendulous, with 

 the raphe away from the axis of the ovary, or erect or ascending. 



a. Flowers regular, or nearly so (except in Hippocastanaceae, which are trees or 



shrubs with digitately compound leaves. 



Petals none (or 3 in Empetrum} ; flowers monrecious or dioecious; leaves evergreen. 

 Stamens mostly 3; low heath-like shrubs. Fam. i. Empetraceae. 



Stamens 4-7 ; our species an herb with broad leaves and spiked flowers. 



Fam. 2. Buxaceae. 

 Petals present; leaves deciduous, except in Cyrillaceae and some Ilicaceae. 



Low annual herbs, with pinnately divided leaves, the stamens twice as many as the 



petals. Fam. 3. Limn ant haceae. 



Trees or shrubs, or rarely herbaceous vines. 



Ovary i-celled (in ours); fruit a small drupe. Fam. 4. Anacardiaceae. 



Ovary 2-several-celled. 



Leaves simple, pinnately veined. 

 Seeds not arilled. 



Fruit dry; flowers racemed, perfect. Fam. 5. Cyrillaceae. 

 Fruit a small drupe: flowers not racemed, mostly polygamo-dice- 



cious: ovules pendulous. Fam. 6. Ilicaceae. 



Seeds arilled; ovules erect; capsule fleshy. Fam. 7. Celastraceae. 

 Leaves simple and palmately veined, or compound. 

 Leaves opposite. 



Fruit a bladdery 3-lobed capsule. Fam. 8. Staphyleaceae. 

 Fruit of 2 winged samaras. Fam. 9. Aceraceae. 



Fruit a leathery capsule; flowers irregular; leaves digitately com- 

 pound. Fam. 10. Hippocastanaceae. 

 Leaves alternate ; fruit various. Fam. n. Sapindaceae. 



b. Flowers very irregular, the posterior sepal large, saccate; succulent herbs, the 



capsule elastically dehiscent. Fam. 12. Balsaminaceae. 



