68 NAIADACEAE 



Los Angeles River, Brannton 571, to the San Joaquin Valley and north to 

 British Columbia and east to the Atlantic coast. 



Var. greenei Graebner. Branches of the inflorescence more erect; achenes 

 rounded at summit. Region of San Francisco Bay (Olema, Lake Merced) 

 south to Lower California and north to British Columbia. 



Refs. SPARGANIUM EURYCARPUM Engelm. in Gray, Man. 5th ed. 481 (1867). Var. GREENEI 

 Graebner in Engler, Pflzr. 4 l : 13 (1900). S. greenei Morong, Bull. Torr. Club, 15: 77 (1888), 

 type loc. Olema, Greene; Jepson, Fl. W. Mid. Cal. 96 (1901). S. californicum Greene, Bull. 

 Cal. Acad. I 1 : 11 (1884), based on material from Calistoga, Sacramento and West Oakland. 



2. S. simplex Huds. Stems erect, 1 to 3 feet high, or sometimes floating; 

 leaves 2 to 6 lines broad, slightly carinate ; inflorescence usually simple ; stam- 

 inate heads 3 to 5, congested or confluent, but distant from the pistillate; 

 pistillate heads 2 to 6, the lowest peduncled, some supra-axillary, 8 or 9 lines 

 in diameter in fruit ; nutlets narrow, 2 to 2y 2 lines long, 1 to l 1 /^ lines thick on 

 the lower third, at apex gradually attenuate into the long style, long-pediceled, 

 often 2-celled. 



Sierra Nevada : Kaweah Meadows ; Silver Lake ; Placer Co. ; Donner Lake ; 

 Goose Lake, Shasta Co.; Modoc Co., Mrs. M. H. Manning. North to British 

 Columbia and east to New England and Newfoundland. 



Ref. SPARGANIUM SIMPLEX Huds. Fl. Angl. 2d ed. 401 (1778). 



3. S. angustifolium Michx. Stems 1 to 4 feet high ; leaves exceedingly long 

 and narrow, 1 to 2 l / 2 lines broad, floating or erect ; inflorescence simple ; stam- 

 inate heads 2 to 6, sometimes blended but distant from the pistillate; pistil- 

 late heads sessile in the axils, often a little supra-axillary, rarely peduncled; 

 nutlets 2!/2 lines long, brownish, constricted at or above the middle, abruptly 

 contracted at apex into the long style or beak, pediceled. 



Lakelets and slow streams: San Bernardino Mts. ace. Parish, north to British 

 Columbia and east to Pennsylvania and Newfoundland. 



Refs. SPARGANIUM ANGUSTIFOLIUM Miehx. Fl. Bor. Am. 2: 189 (1803); Graebner in 

 Engler, Pflzr. 4 10 : 16 (1900). S. simplex var. angustifoUum Engelm. in Gray, Man. 5th ed. 

 481 (1867); Parish, Erythea, 6: 85 (1898). 



NAIADAOEAE. PONDWEED FAMILY. 



Water plants entirely submerged or with floating leaves. Leaves thread- 

 like or grass-like or some with broad floating blades, commonly sheathing at 

 base or with sheathing stipules. Flowers inconspicuous, naked or with a very 

 small calyx, commonly borne on a short spike or spadix. Ovaries 1 to 4, distinct, 

 free from the calyx if that be present, 1-celled, 1-ovuled, ripening into nutlet- 

 like fruits. Ten genera, the species of mostly wide distribution. 



Bibliog. Tuckerman, Edw., Potamogeton (Am. J. Sci. 2d ser. vol. 6, pp. 224-30, 1848; 

 vol. 7, pp. 347-60, 1849). Morong, T., Naiadaceae of North America (Mem. Torr. Club, 

 vol. 3, no. 2, 1893). Dudley, Genus Phyllospadix (Wilder Quarter-century Book, pp. 403- 

 420, pis. 1-2, 1893). Fryer, A., Potamogetons of the British Isles (1898). Rendle, A. B., 

 Naiadaeeae (Engler, Pflzr. teil 4, abt. 12, 1901). Campbell, D. H., Morphological study of 

 Naias and Zannichellia (Proc. Cal. Acad. 3rd ser. Bot. vol. 1, pp. 1-70, pis. 1-5, 1897). Ascher- 

 son & Graebner, Potamogetonaceae (Engler, Pflzr. teil 4, abt. 11, 1907). 

 Flowers perfect, in spikes or clusters. 



Calyx of 4 distinct sepals 1. POTAMOGETON. 



^ Calyx none 2. RUPPIA. 



Flowers unisexual ; calyx none. 



Leaves entire. 



Pistils about 4, borne in a cup-shaped involucre; fresh water ponds or streams 



3. ZAN T NICHELLIA. 





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