54 JUNCACEAE. 



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 very slender, 3-6 cm. long; capsule 1 -celled, 

 6-8 mm. long. Marshall Junction, Suksdorf. 



Family 20. JUNCACEAE. RUSH FAMILY. 



Perennial, grass-like, usually tufted herbs; inflorescence a com- 

 pound 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 bractlets; 

 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. 73. JUNCUS, 54. 



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



basal. 74. JUNCOIDES, 57. 



73. JUNCUS. RUSH. 



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

 leaves glabrous, round, grass-like or channeled; inflorescence a 

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

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

 Ibut 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 continu- 

 ation of the stem, the inflorescence therefore appearing 

 lateral. 

 Flowers solitary or in clusters of 2 or 3. 



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



Inner sheaths bearing a leaf blade; capsule acute. /. parryi. 

 Flowers numerous, in compound panicles. 



Perianth segments brown, a green stripe on each side 

 of the midrib; leaf of the inflorescence usually 

 much shorter than the stem. /. balticus. 



Perianth segments green; leaf of the inflorescence as 



long as the stem. /. filiformis. 



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 channeled. 

 Annuals; stems branched, leafy. 



Capsule oblong. /. bufonius. 



Capsule globose. / sphaerocarpus. 



Perennials; stems simple. 



Flowers bracteolate, loosely scattered or some- 

 what congested but not in true heads. 



