74 NAIADACEAE 



2. RUPPIA L. 



Immersed aquatic herbs with long tilit'orm forking stems. Leaves almost 

 capillary, with a broad membranous sheathing base. Peduncles slender, axil- 

 lary, at hrst very short and enclosed in the spathe-like base of the leaf, each 

 bearing two flowers disposed near together and rising to the surface in the 

 pei'iod of authesis, afterwards coiling and drawing the fruits beneath the 

 surface. Flowers perfect, entirely destitute of perianth. Stamens 2, sessile, 

 each anther consisting of 2 large and separate anther-cells. Pistils 4, after 

 flowering becoming stalked and ripening into hard ovoid nutlets; stigmas 

 depressed, sessile.- — One species. (H. B. Ruppius, a German botanist of the 

 18th century.) 



1. R. maritima L. Ditch-grass. Plants 2 to 3 feet long; leaves 2 to 3 

 inches long; nutlets % to 1^/4 lines long, raised on stipes 1 to 12 lines long; 

 fruiting peduncle 3 to 6 lines long. 



Alkaline or brackish waters: southern California northward through the 

 state. Cosmopolitan. 



Refs.— RUPPIA MABITIMA L. Sp. PI. 127 (17.53); Wats. Bot. C'al. 2: 194 (18S0) ; Jepson, 

 Fl. W. Mid. Cal. 101 (1901). 



3. ZANNICHELLIA Mich. 



Immersed aquatic plants, Howering and fruiting under water, the thread-like 

 stems from a creeping rootstock. Leaves opposite or in whorls. Flowers 

 monoecious, without perianth, sessile, both kinds in the same axil: staminate 

 flowers consisting of an anther on a pedicel-like filament; pistillate flowers 

 2 to 6 (usually 4) in a cluster and surrounded by a hyaline cup-shaped in- 

 volucre shorter than the pistils, each flower consisting of a single pistil with a 

 thin peltate stigma on the summit of the short style. Fruit an oblong some- 

 what flattened, beaked nutlet. — One species. (G. G. Zannichelli. 1662 — 1729, a 

 botanist of Venice.) 



1. Z. palustris L. Horned Pondweed. Stems spai'ingly branched, 1 to 11/2 

 feet long ; leaves 1 to 2 inches long, filiform but flat ; nutlet slightly incurved, 

 becoming stipitate, 1 to II/2 lines long, often roughened or toothed on the back. 



Pools and still waters of streams: Los Angeles, Santa Barbara and north- 

 ward to San Leandro Creek, N. L. Gardner, and the Sacramento Valley. Nearly 

 throughout North America. Cosmopolitan. 



Eefs.— ZANNICHELLIA PALUSTBis L. Sp. PI. 969 (1753); Wats. Bot. Cal. 2: 193 (1880); 

 Morong, Mem. Torr. Club, 3=: 57, pi. 64 (1893) ; Jepson, Fl. W. Mid. Cal. 101 (1901). 



•4. ZOSTERA L. Grass-wrack. 



Submerged maritime herbs with elongated and very narrow grass-like radi- 

 cal leaves and inflorescences raised on peduncle-like stems. Flowers monoe- 

 cious, borne in 2 rows on the face of a flattened spadix with or without small 

 lateral appendages covering them in the bud and closely invested by a protect- 

 ing leaf-like spathe until anthesis. Staminate flower of 1 stamen. Pistillate 

 flower of 1 pistil. Nutlet ovoid. — North and south temperate zones, 5 species. 

 (Greek zoster, a girdle or band, on account of the ribbon-like leaves.) 



1. Z. marina L. Eel-grass. Leaves with long sheathing bases. 3 to 7-nerved, 

 1 to 4 feet long, 1 to 4 lines broad; spathes jointed at base, ending above in a 

 more or less elongated leaf -like summit; spadix 2 to 4 inches long, 10 to 20- 

 fruited; fruits l^/^ lines long, the ribs of the seed showing clearly on the 

 pericarp. 



Shoal waters of bays, San Pedro to San Francisco Bay and north to Alaska. 



