18 CLASS III. ORDER III, 



on the inside, varying in their proportions to the bractes, but 

 commonly longer. Outer petals slender, spreading, purple at 

 the edge, yellow, and veined in the middle, the yellow portion 

 much greater than in the last species. Inner petals lanceolate, 

 slightly emarginate. Germs oblong, three sided ; sides Avith 

 two deep parallel grooves, the whole representing a cylinder 

 with three smaller ones attached to its sides. As the germ en- 

 larges, the distance between the two furrows does not increase, 

 and they are nearly obliterated in the capsule, which is triangu- 

 lar and turgid with its three rows of seeds. 



Found at South Boston and Cambridge, in the same places 

 with Iris Virginica, but much less frequent. — June. — Perennial. 



19. XYRIS. 

 Xyris Jupicai. MicTi. Yellow eyed grass. 



Leaves linear, somewhat obtuse ; scape near the 

 head dilated, two edged ; scales rounded. 

 Sijn. Xyris Caroliniana. Lam. Pair. 



Root bulbous ; leaves grassy, shorter than the scape ; scape 

 erect, two edged, twisted, a little widened at top. Heads round- 

 ish, rather acute, supporting a number of small yellow florets 

 projecting out of the scales, hairy within, and consisting of three 

 ovate, crenate petals.^ — Meadows. — July, August. — Perennial. 



20. SCHGENUS. 

 ScHfENus MARiscoiDES. Muhl. Water Bog rush. 



Culm round; leaves cliannelied; umbel terminal, 

 spikes faKcicied. 



A firm rusb a foot or two high. Leaves half cylindrical, chan- 

 nelled. Fascicles about three together, each containing a dozen 

 lanceolate, brown spikes. — Edges of Fresh Pond. — July. — Pe- 

 rennial. 



<5> Subgenus Rhyncospora. Seed surrounded toith bristles — style 

 •persistent. 



ScH(ENus ALBi;s. L. Wliitc licadcfl Bog rush. 



Culm three sided, leafy; flowers fascicled; leaves 

 setaceous. 



