WATER-PLANTAIN FAMILY 



99 



2. MACHAEROCARPUS Small. N. Am. Fl. 17: 44. 1909. 



Perennial scapose lierbs. Leaves erect, ascending or floating, long-petioled, 3-5-veined, 



not lobed at the base. Flowers perfect, borne in simple panicles. Sepals 3, broad-ribbed, 



persistent. Petals 3, white or pink, spreading, incised, deciduous. Stamens 6, 2 opposite each 



sepal ; filaments flattened ; anthers elongate. Carpels few in one whorl, attached to the conic 



receptacle by their broad bases ; ovules solitary in each carpel. Achenes in one radiant 



whorl, ribbed on back, faces depressed, beak erect, as long as the achene body or longer. 



A nionotypic genus peculiar to California, dif- 

 fering from the Old World genus Damasonium by 

 the uni-ovulate instead of bi- or multi-ovulate 

 carpels. 



L Machaerocarpus californicus 



(Torr.) Small. 



Fringed Water-plantain. Fig. 208. 



Damasonium calif ovnicum Torr.; Benth. PI. Hartw. 



341. 1857. 

 Alisina californicum Micheli, in DC. Monogr. 



Phan. 3: 34. 1881. 



Leaves oblong to ovate or linear-oblong, 

 2.5-6 cm. long, obtuse at the apex, obtusei 

 to subcordate at the base ; the petioles, at 

 least some of them, much longer than the 

 blades ; scapes usually several together, 

 erect or decumbent, 1-4 dm. long ; pedicels 

 loosely spreading or recurving at least in 

 fruit ; sepals broadly oblong or ovate-ob- 

 long, 4-5 mm. long; petals suborbicular, 

 8-10 mm. long, more or less irregularly 

 incised ; achenes dagger-like, 6-10, hori- 

 zontally radiating, 7-12 mm. long, the beak 

 subulate. 



Shallow water or in mud. Upper Sonoran Zone; 

 California, Modoc County (Honey Lake), through 

 the Sacramento Valley and Sierra foothills to 

 Sierra County; also in the coastal region near 

 Petaluma, Sonoma County. Type locality: Sacra- 

 mento Valley, near Chico. 



3. ECHINODORUS Rich. ; Engelm. in A. Gray, Man. 460. 1848. 



Perennial or annual herbs with long-petioled, elliptic-ovate or lanceolate, often cordate 

 or sagittate leaves, 3-9-ribbed and mostly punctate with dots or lines. Scapes often longer 

 than the leaves. Inflorescence racemose or paniculate. Flowers perfect, in whorls, each 

 whorl with 3 outer bracts and numerous inner bracteoles. Petals white. Receptacle large, 

 convex or globose. Stamens 12-30. Ovaries numerous ; style obliquely apical, persistent ; 

 stigmas simple. Achenes more or less compressed, ribbed and beaked, forming spinose heads. 

 [Greek, in reference to the prickly fruit.] 



A genus of about 14 species distributed over the temperate and tropical regions of America, Europe, and 

 Africa. Type species, Alisma rostratum Nutt. 



Style shorter than the ovary; beaks about one-fourth the length of the achene. 1. E. radicans. 



Style longer than the ovary; beak half the length of the achene. 2. E. cordifolius. 



1. Echinodorus radicans (Nutt.) Engelm. 



Creeping Bur-head. 



Fig. 209. 



Sagittaria radicans Nutt. Trans. Am. Phil. Soc. II. 5: 



159. 1837. 

 Echinodorus radicans Engelm. in A. Gray, jMan. ed. 2, 



438. 1856. 



Leaves coarse, ovate, obtuse at the apex, 

 cordate at the base, 5-20 cm. long ; petioles 1-7 

 dm. long ; scapes elongate, prostrate, creeping, 

 3-12 dm. long, often solitary; whorls of the in- 

 florescence remote ; pedicels 3-12 in a whorl, 

 unequal, 1.5-6 cm. long; bracts linear-lanceolate 

 from dilated bases ; sepals ovate or orbicular- 

 ovate, 5-6.5 mm. long, obtuse; petals white, some- 

 what longer than the sepals ; fruiting heads de- 

 pressed, globose or ovoid, 7-9> mm. in diameter; 

 achenes 2 mm. long, the body falcate, 6-10-ribbed, 

 the beak about one-fourth as long as the body, 

 incurved. 



Borders of pools or ditches. Upper and Lower Sonoran 

 Zones; Illinois and Missouri to Florida, Texas and south- 

 ern California. Type locality: Fort Smith, Arkansas. 



