GENUS i. 



EEL-GRASS FAMILY. 



9 1 



on a one-sided spadix and enclosed in a close fitting ultimately rupturing spathe. 

 Perianth none, but some of the flowers covered by a hyaline envelope. Staminate 

 flower of a single, sessile, i-celled anther. Pistillate flower of two, united carpels, 

 'with a short or elongated style and 2 thread-like stigmas. Seeds ribbed or smooth. 



Represented in North America by two genera, one Pacific and the following : 



i. ZOSTERA L. Sp. PI. 968. 1753. 



Marine plants with slender rootstocks and branching compressed stems. Leaves 2-ranked, 

 sheathing at the base, the sheaths with indexed margins. Spadix linear, contained in a spathe. 

 Flowers monoecious, arranged alternately in 2 rows on the spadix. Stawinate flower merely 

 an anther attached to the spadix near its apex, i-celled, opening irregularly on the ventral 

 side; pollen thread-like. Pistillate flower fixed on its back near the middle; ovary i; style 

 elongated; stigmas 2, capillary; mature carpels flask-shaped, membranous, rupturing irregu- 

 larly beaked; seeds ribbed; embryo ellipsoid. [Greek, referring to the ribbon-like leaves.] 



About 6 species of marine distribution, the following the type of the genus. 



i. Zostera marina L. Eel-grass. Grass-wrack or Sea-wrack. Fig. 216. 



Zostcra marina L. Sp. PI. 968. 1753. 



Leaves ribbon-like, obtuse at the apex, i-6 

 long, i "-4" wide, with 3-7 principal nerves. Spa- 

 dix i'-2i' long; flowers about 3" long, crowded, 

 usually from 10-20 of each kind on the spadix; 

 ovary somewhat vermiform ; at anthesis the stig- 

 mas are thrust through the opening of the spathe 

 and drop off before the anthers of the same 

 spadix open ; the anthers at anthesis work them- 

 selves out of the spathe and discharge the glutin- 

 ous stringy pollen into the water; seeds cylindric, 

 strongly about 2O-ribbed, about ii" long and \" 

 in diameter, truncate at both ends, the ribs show- 

 ing very clearly on the pericarp. 



In bays, streams and ditches along the Atlantic 

 Coast from Greenland to Florida and on the Pacific 

 from Alaska to California. Also on the coasts of 

 Europe and Asia. Called also Wrack or Widgeon- 

 grass ; Sea, Sweet, Barnacle and Turtle-grass, Grass- 

 weed, Tiresome-weed, Bell-ware, Drew. Summer. 



Family 6. SCHEUCHZERIACEAE Agardh, Theor. Syst. PI. 44. 



ARROW-GRASS FAMILY. 



I8 5 8. 



Marsh herbs with rush-like leaves and small spicate or racemose perfect 

 flowers. Perianth 4-6-parted, its segments in two series, persistent or deciduous. 

 Stamens 3-6. Filaments very short or elongated. Anthers mostly 2-celled and 

 extrorse. Carpels 3-6, i-2-ovuled, more or less united until maturity, dehiscent 

 or indehiscent. Seeds anatropous. Embryo straight. 



Four genera and about 10 species of wide geographic distribution. 

 Leaves all basal ; flowers numerous on naked scapes, spicate or racemed. 

 Stem leafy ; flowers few in a loose raceme. 



1. Triglochin. 



2. Scheuchzeria. 



i. TRIGLOCHIN L. Sp. PI. 338. 1753. 



Marsh herbs with basal half-rounded ligulate leaves with membranous sheaths. Flowers 

 in terminal spikes or racemes on long naked scapes. Perianth-segments 3-6, concave, the 3 

 inner ones inserted higher up than the outer. Stamens 3-6; anthers 2-celled, sessile or nearly 

 so, inserted at the base of the perianth-segments and attached by their backs. Ovaries 3-6, 

 i-celled, sometimes abortive; ovules solitary, basal, erect, anatropous. Style short or none. 

 Stigmas as many as the ovaries, plumose. Fruit of 3-6 cylindraceous oblong or obovoid 

 carpels, which are distinct or connate, coriaceous, costate, when ripe separating from the base 

 upward from a persistent central axis, their tips straight or recurved, dehiscing by a ventral 

 suture. Seeds erect, cylindraceous or ovoid-oblong, compressed or angular. [Greek, in allu- 

 sion to the three-pointed fruit of some species.] 



About 9 species, natives of the temperate and subarctic zones of both hemispheres. Type 



species : Triglochin palustris L. Only the following are known to occur in North America. 

 Carpels 3. 



Fruit Hnear or clavate, tapering to a subulate base. i. T. palustris. 



Fruit nearly globose. 2. T. striata. 



Carpels 6 ; fruit oblong or ovoid, obtuse at the base. 3. T. maritima. 



