54 JUNCACEAE. 



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

 30-KM) ,111. long; leaves sessile, linear, acute; spathe terminal, 1-flowered; 

 Bowl Cl small, pale yellow, the tube very slender, 3-6 cm. long; capsule 1-celled, 

 6-8 nun. 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 <>r 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 

 parittal 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, 

 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 continu- 

 ation of the stem, the inflorescence therefore appearing 

 lateral. 

 Flowers military or in clusters of 2 or 3. 



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



Inner sheaths bearing a leaf blade; capsule acute. J. 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. J. balticus. 



Perianth segments green; leaf of the inflorescence as 

 1. >ng as the stem. /. fiUformis. 



• "f the inflorescence not appearing like a con- 

 tinuation of the stem. 

 1 i aves not provided with cross partitions, either flat and 

 grass-like or terete and channeled. 

 Annuals; Btems branched, leafy. 



mule oblong. /. bufonius. 



( apsule globose. J. sphaerocarpus. 



Pen nnials; stems simple. 



1 lowers bracteolate, loosely scattered or some- 

 what congested but not in true heads. 



