178 CONTKIBUTIONS FROM THE NATIONAL HERBARIUM. 



PONTEDERIACEAE. Pondweed Family. 



HETERANTHERA. 



1. Heteranthera dubia (Jacq.) MacM. Met. Miun. V.iH. 1892. 

 Comirielina duoia Jacq. Obs. Bot. 3 : 9. j>l. 59. 1768. 



SchoUera graminifolia Willd. Neue. Sclir. Ges. Naturf. Fr. 3: 438. 1801, iioiu. iiud. 

 Heteranthera graminea Vahl, Enum. 2: 45. 1806. 

 Leptanthus gramineus Michx. Fl. 1 : 25. 1803. 



Type locality: The type specimen is Clayton's nmnbcr 814, probaljly from Virginia. 

 Range: Washington to Ontario, south to Mexico and Florida. 

 Specimens examined: Hangman or Latali Creek near Marshall Junction, Sulcsdorf. 



JUNCACEAE. Rush Family. 



Leal" slleaths open; capsule 1 or 3-celled, many-seeded; placentae pari- 

 etal or axial JuNCUS (p. 178). 



Leaf sheaths closed; capsule 1-ceIled, 3-seeded; placenta ba.sal Juncoiues (p. 184). 



JUNCUS. Rush. 



Lowest leaf of the inflorescence appearing like a continualiim of 

 the stem, the inflorescence therefore seemingly latei'al. 

 Flowers in compound panicles, usually numerous. 



Stamens 3; leaf of the inflorescence much shorter than 

 the stem. 



Perianth green ; panicle loose \. J . cffusus. 



Perianth brown; panicle close la. J. effvsus hesperius. 



Stamens 6. 



Perianth green; leaf of the inflorescence as long as 



the stem 2. J.filifonnis. 



Perianth parts brown, a green stripe each side of the 

 midrib. 



Flowers 3 to 4.5 mm. long 3. J. halticua. 



Flowers 5 to 6 mm. long 4. J. lescurii. 



Flowers few, 1 to 3 in each cluster. 



Inner sheaths bristle-tipped; capsule retuse. 5. J. snhtrijjorus. 



Inner sheaths leaf-bearing; capsule acute 6. J. parryi. 



Lowest leaf of the inflorescence not appearing like a continuation 

 of tlie stem. 



Leaves not provided with cross-partitions, either flat and 

 grass-like or terete and channeled. 



Flowers bracteolate, loosely scattered or somewhat con- 

 gested but not in heads. 



Annuals; stems branched, leafy. 



Stamens 6; flowers loosely scattered. 



Capsule oblong 7.-7. hifonius. 



Capsule globose 8. J. sphacrocarpus. 



Stamens 3. 



Inflorescence 1-flowered; bract 1 9. J. nnciaJis. 



Inflorescence few-flowered; bracts 2 or 



more, style slioi't 10. r/. Jiniclnistylus. 



Perennials; stems simple. 



Perianth segments 2.5 to 4 mm. long; capsule 



3-celled; panicle close 11.,/. cuiifiisus. 



