JUNCACEAE. 87 



Heteranthera dubia (Jacq.) MacM. Stems slender, branched, leafy, 30- 

 100 cm. long; leaves sessile, linear, acute; spathe terminal, 1-flowered; flowers 

 small, pale yellow, the tube ver>' slender, 3-6 cm. long; capsule 1-celled, 6-8 

 mm. long. 



In ponds, rare in our limits. Sauvies Island, Oregon, Howell. 



Family 21. JUNCACEAE. Rush Family. 



Grass-like, usually tufted herbs mostly perennials; inflorescence 

 a compound panicle, corymb or umbel, with the flowers singly or 

 loosely clustered or aggregated into spikes or heads, rarely reduced 

 to a single flower; flowers small, regular, with or without bract- 

 lets; perianth 6-parted, the parts glumaceous; stamens 6, rarely 

 3; pistil superior, tricarpellary; ovary 3-celled, or 1-celled with 

 3 parietal placentae; ovules 3-many; stigmas 3; fruit a loculicidal 

 capsule; seeds 3-many, small. 



Leaf-sheaths open; capsule 1- or 3-celled, many-seeded; 



placentae parietal or axial. 105. JuNCUS, 87. 



Leaf-sheaths closed; capsule 1-celled, 3-seeded; placen- 

 tae basal. 106. JuNCOiDES, 91. 



105. JUNCUS. Rush. 



Annual or perennial plants; stems leaf-bearing or scapose; 

 leaves glabrous, cylindrical, flat or channeled; inflorescence a 

 panicle or corymb, often one-sided, bearing its flowers either 

 singly and with 2 bractlets or in heads and without bractlets, 

 but each head in the axil of a bract; stamens 6, rarely 3; ovary 

 1-celled or 3-celled; placentae parietal or axial; seeds several to 

 many. 



Lowest leaf of the inflorescence appearing like a continua- 

 tion of the stem, the inflorescence therefore seemingly 

 lateral. 

 Flowers in compound panicles, usually numerous. 



Stamens 3; leaf of the inflorescence much shorter 



than the stem. J. effusus. 



Stamens 6. 



Flowers 3-4.5 mm. long. /. balticus. 



Flowers 5-6 mm. long. J. lesciirii. 



Flowers few, 1-3 in each cluster. 



Inner sheaths bristle-tipped; capsule retuse. J. subtriflorus. 



Inner sheaths leaf-bearing; capsule acute. /. parry i. 



Lowest leaf of the inflorescence not appearing like a con- 

 tinuation of the stem. 

 Leaves not provided with cross-partitions, either flat and 

 grass-like or terete and channelled. 

 Flowers not bracteolate, in true heads. 



Perianth shorter than the capsule; heads several- 

 many, 3-5-flowered. /. covillei. 

 Perianth longer than the capsule; heads solitary 

 or few. 



