512 WlEGAND : J UNCUS TENUIS WlLLD. 



vegetative characters, especially those referring to the sheath and 

 its auricles as well as upon the leaf-blade, perianth and capsule. 

 The seeds have not been found of great service since in this group 

 except in one or two cases they are very much alike. Neither has 

 the density of the inflorescence served definitely to distinguish 

 species, since in many species this seems to be influenced greatly by 

 the conditions of growth, soil, exposure, etc. The species are all 

 perennial and all have six stamens, consequently these characters 

 are omitted from the following descriptions. 



Through the kindness of Professor Robinson it was possible to 

 supplement the Cornell Herbarium material with all the material 

 in the Gray Herbarium. The New England Botanical Club also 

 loaned many specimens from the Eastern States, and Mr. M. L. 

 Fernald placed at the writer's disposal a large mass of material 

 from various localities in Maine. 



Synopsis of the Species 



Sheaths covering one half the length of the stem or more ; perianth parts obtuse, equal- 

 ing or shorter than the 3-celled capsule. I* J. Gerardu 

 Sheaths covering only about one fourth of the stem ; perianth segments acute or 



pungent. 

 Seeds long-caudate ; leaves "terete, bracts scarcely exceeding the stramineous in- 

 florescence ; perianth (3.5-4.5 mm.) equaling the oblong 3-celled capsule. 



Seeds not caudate. 



2. J. Caseyi. 



Capsule longer than the small (2.5-3 mm.) perianth, 3-celled ; leaves terete, 



bracts much exceeding the fuscous cyme. 3. J. Greenti. 



Capsule equaling or shorter than the commonly larger ( 2.5-5 mm. ) perianth ; 



leaves various. 

 Leaves flat but often involute, cross-section lunate. 



Auricles at summit of sheath membranous, whitish, scarcely scarious, 



rarely produced beyond the ^insertion ; capsule 3-celied or 

 nearly so ; perianth scarcely spreading, often appressed. 

 Perianth small (2. 5-4 mm. ), equaling the capsule. 



Flowers conspicuously secund, 2.5-3.5 mm. long ; capsule 

 oval ; plant slender with close sheaths ; bract shorter 

 than the cyme. 4. J. secundus. 



Flowers scarcely secund, 3-4 mm. long ; capsule ovate- 

 oblong ; plant taller and stouter, much looser sheaths ; 

 bracts 2, exceeding the cyme. 5. J. interior. 



Perianth larger (4-5-5 mm.), exceeding the capsule. 



Plant stout, 4-7 dm. high ; anthers and style very short. 



6. J. ArizoJiictts. 



Plant more slender, 3 dm. high ; anthers linear, exceeding 



the filaments ; styles often 1-I.5 mm. long." 



7. J. Georgiamts. 



