CALLITRICHACEAE (WATER STARWORT FAMILY) 311 



petioled leaves: involucres in terminal clusters, oblong-campanulate, about 

 3 mm. long, 3-5-lobed, with 1-4 short-pediceled glands without appendages: 

 capsules glabrous: seeds ovoid or subglobose, slightly tuberculate. Extend- 

 ing into Colorado from the east. 



11. Euphorbia Aliceae A. Nels. Bot. Gaz. 42: 50. 1906. Perennial from 

 slender horizontal rootstocks, glabrous or slightly pubescent, 10-15 cm. high: 

 stem branching from the base, the branches spreading-decumbent : leaves 

 narrowly oblanceolate, short-petioled, sharply- serrate, opposite, more crowded 

 toward the terminal clustered involucres: involucres nearly sessile, small, 

 turbinate, somewhat fimbriate-margined ; the glands about 4, small, short- 

 stipitate, sometimes minutely cornuate or even obscurely appendaged: cap- 

 sules glabrous: seeds cubical, with a caruncle, slightly tuberculate, ashy. 

 Known as yet only from Hartville, Wyoming. 



12. Euphorbia cuphosperma (Engelm.) Boiss. in DC. Prodr. 152; 73. 1862. 

 Annual, sparingly rough-pubescent : stem simple or somewhat branched up- 

 ward with erect slender branchlets, 2-5 dm. high: leaves opposite or alter- 

 nate, narrowly linear-lanceolate, acute, subentire: involucres 3-5, corymbose, 

 subsessile, campanulate, with ovate lobes; glands 4, long-stipitate, unappen- 

 daged: seeds irregularly 4-angled and slightly tuberculate. From Dakota 

 to Mexico. 



13. Euphorbia robusta (Engelm.) Small, in Brit. Fl. 2: 381. 1897. Gla- 

 brous: stems short, stout, tufted on the crown of a perpendicular rootstock, 

 1-2 dm. high: leaves scattered, oblong-ovate, 10-14 mm. long, entire, obtuse, 

 sessile: involucres terminal in a 3-5-rayed umbel, campanulate, bearing 4 

 unappendaged crescent-shaped glands: capsule of 3 ovate rounded lobes: seeds 

 terete, gray, minutely pitted. E. montana in part. Montana to Colorado. 



14. Euphorbia montana Engelm. Bot. Mex. Bound. Surv. 192. 1859. 

 Resembling the preceding but the stems few, slender and taller, somewhat 

 branched below the umbel: usually somewhat pubescent on the involucre and 

 the floral leaves: glands short-stipitate and bearing 2 short horn-like pro- 

 tuberances: seeds ovoid-oblong, asn-colored, deeply and irregularly pitted. 

 Southern Colorado and to the southwest ward. 



15. Euphorbia arkansana Kngelm. it Gray, Bost. Journ. Nat. Hist. 5: 53. 

 L845. Annual, glabrous, erect, branching above, 2-5 dm. high: stem leaves 

 few, cuneate-spatulate or oblanceolate, 1-5 cm. long; upper leaves oblong to 

 triangular-ovate: involucre small, its lobes short; glands yellow, transversely 



'liptical: capsule depressed-globose, more or less warty: seeds ovoid-lenticular, 

 itn sharp reticulations. E. <l/cti/<>xi>er>n<i. Quite variable. Several varieties 

 : been characterized by J. B. S. Norton in the Eleventh Rep. Mo. Bot. 

 I. From Wyoming to Mexico. 



i. Euphorbia manca A. Nels. 1. c. 47: 437. 1909. Annual, the decumbent 

 : giving rise to few-several simple erect branches 1-2 dm. high: leaves 

 obovate-cuneate, broadly obtuse, numerous, lower reduced: primary floral 

 ' 'acts ovate-renif orm ; secondary broadly reniform, sometimes connate: in- 

 >rescence once or twice trichotomous: capsule about 4 mm. long: seeds short, 

 jylindrical-oblong, gray but not ashy, nearly smooth. Colorado. 



17. Euphorbia commutata Engelm. in Gray Man. Ed. 2. 389. 1856. Bien- 

 iial, branched from the base, glabrous, 1-3 dm. high: leaves scattered, thin 

 ind membranaceous, petioled, round-obovate or the upper ovate: umbels 

 srminal, 3-rayed and again forking or 3-rayed: involucres campanulate, 

 ssile; glands 3-4, unappendaged, prolonged into slender horns : capsule 

 )tusdy angled, glabrous: seeds terete, irregularly pitted. Extending into 

 range from the eastward. 



65. CALLITRICHACEAE Lindl. WATER STARWORT FAMILY 



Small, slender, aquatic herbs, with opposite entire leaves, no stipules, and 

 monoecious, axillary flowers without perianth, but sometimes with 2 bracts. 

 Stamen 1 with slender filament and heart-shaped 4-celled anther. Ovary 



