CALLITRICHACEAE 723 



1. calli'triche L. 



Characters of the family. Watek Stakwort. 



Fruit manifestly pedicelled. 



Fruit about 0.8 mm. long: styles persistent. 1. C. Austinii. 



Fruit about 0.7 mm. long : styles deciduous. 2. C. Nuttallii. 



Fruit essentially sessile. 



Styles much shorter than the fruit. 8. G. palustris. 



Styles fully as long as the fruit. 



Aquatic: fruit 1 mm. broad. 4. C. hcterophylla. 



Terrestrial : fruit 0.5 mm. broad. 5, C. peploides. 



1. Callitriche Austinii Engelm. Terrestrial, glabrous, fragrant in drying. Stems 

 erect or decumbent, 1-5 cm. long : leaf-blades spatulate, 2-3 mm. long, obtuse, 3-nerved, 

 sessile or with winged petioles, destitute of scales : pedicels shorter than the fruit or rarely 

 slightly longer : fruit broader than long, notched at both ends, about 0.8 mm. broad, the 

 2 lobes grooved around the edges, the narrow wings denticulate : styles shorter than the fruit, 

 persistent. 



In damp shaded soil, New York to Missouri, New Jersey, Louisiana and Mexico. Summer to fall. 



2. Callitriche Nuttillii Torr. Terrestrial, the foliage destitute of stellate scales. 

 Stems 2-6 cm. long, sometimes much branched, often creeping : leaf-blades spatulate or 

 elliptic, 2-4 mm. long, obtuse, 3-nerved : pedicels shorter than the fruit, witliout scales, 

 finally deflexed : fruit broader than long, 0.7 mm. broad, notched at both ends, the 2 lobes 

 deeply grooved, finally separating, the segments margined : styles deciduous. 



In moist soil, Kentucky to Alabama and Louisiana. Spring and summer. 



3. Callitriche palilstris L. Aquatic, bright green, foliage with stellate scales. 

 Stems usually lioating, 2-30 cm. long : leaf- blades 0.5-1.5 cm. long, the submersed ones 

 linear, sessile, notched or cleft at the apex, commonly 1-nerved : emersed leaves spatulate, 

 the blades 3-nerved, rounded or retuse at the apex, narrowed into winged petioles : pedicels 

 nearly wanting, furnished with 2 scales : fruit obovoid, about 1.5 mm. long, slightly 

 notched at the apex, the 2 lobes deeply grooved, the segments winged, especially above, 



the wings undulate : styles shorter than the fruit. [C. verna L.] 



In ditches and streams, throughout southern British America and the United States. Also in 

 South America, Europe and Asia. Spring to fall. 



4. Callitriche' heterophylla Pursh. Usually aquatic, foliage furnished with stellate 



scales. Stems floating, or rarely creeping in the mud, 3-30 cm. long : leaves various ; 



the submersed ones filiform or linear, the emersed ones with spatulate blades, rounded or 



retuse at the apex, 3-5-nerved, narrowed into winged petioles : pedicels with 2 scales : fruit 



broadly obovoid, about 1 mm. long, notched at tlie apex, the 2 lobes shallowly grooved, 



the segments wingless or with narrow wings : styles longer than the fruit. 



In slow-flowing streams, pools and ditches, North America except the extreme north and east of the 

 Rocky Mountains. Summer. 



5. Callitriche peploides Nutt. Terrestrial, fragrant in drying. Stems branching, 

 2-7 cm. long, forming wide mats : leaf-blades obovate, oblanceolate or elliptic, 2-5 mm. 

 long, obtuse, sessile or 3-nerved blades narrowed into short petioles : fruit sessile or nearly 

 so, minute, 0.5 mm. broad, deeply notched at the apex, the 2 lobes grooved, their margins 

 obtuse : styles as long as the fruit or longer. 



On moist soil, Arkansas to Florida and Texas. Spring and summer. 



ORDER 17. SAPINDALES. 



Shrubs or trees, or in the case of Limnanthaceae, herbs. Leaves various : 

 blades simple and entire, toothed, or pinnately parted in the case of annual 

 herbs, or compound. Calyx of distinct sepals. Corolla of distinct petals, regu- 

 lar or rarely irregular, or wanting. Androecium of as many stamens as there 

 are petals, or twice as many, or rarely more or fewer. Filaments distinct. 

 Gynoecium of one carpel or of several carpels united into a compound pistil. 

 Ovary superior. Ovules 1 or 2, or several in each cavity of the ovary, pendu- 

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



Corolla wanting : stamens 4 (in our genus) : styles wanting. Fam. 1. Buxaceae. 



Corolla present or if wanting {Dodonaeaceae) stamens 6: styles present, 

 united. 

 A. Stigmas tufted or many-cleft. Fam. 2. Empetraceae. 



