North American Cyj^tracca. G31 



a. Culm 4 — 5 feet high, umbel very large, supradecom- 

 pounded and proliferous, patulous, nodding, shorter than the 

 involucre ; spikes all pedunculate ; nut white. 



ft. Like the preceding, but the spikes aggregated 3 — 5 

 together at the extremity of the ultimate rays. 



/. With the characters of (a), but the nut brown. 



5. Culm slender, 18 inches high; umbel contracted, some- 

 what erect. 



f. Resembling the last, with the spikes all pedicellate. 



(^. Umbel much crowded, somewhat capitate. 



-n. Umbel somewhat patulous, longer than the involucre, 

 blackish at the base ; spikes oblong, pedicellate. 



Culm nearly terete below, obtusely triangular above, leafy nearly to 

 the summit. Leaves 1 — 2 feet long, flat, 2 — 4 lines wide, scabrous on 

 the margin; sheaths smooth, close, brownish and scarious at the throat. 

 Involucre of 3 — 4 long leaves resembling those of the culm, and several 

 shorter ones, their sheathing bases brownish or nearly black. Umbel 

 consisting of numerous primary rays, which are many times divided. 

 Spikes 2 — 3 lines long, obtuse. Scales acute, of a ferruginous colour 

 when mature, with a green keel. Bristles, when extended, 8 — 10 times 

 as long as the nut, brownish, completely covering the mature spike, 

 giving it a woolly appearance. Stamens 3. Nut flat on the back, 

 obtuse-angled in fruit, long, acuminated, dull. 



Hab. Borders of swamps and wet meadows; Hudson's 

 Bay! to the Gulf of Mexico ! and west to Kentucky ! 



Obs. This species varies much in size and in the appear- 

 ance of its umbel, but the different forms which it assumes pass 

 into one another so gradually, that it is extremely difficult to 

 mark their limits. Along the sea coast, and a short distance in 

 the interior the first two varieties are almost exclusively found, 

 but they rarely occur far inland, while the remaining forms are 

 never seen in the neighbourhood of salt water, nor, as far as my 

 observations have extended, south of the Hudson and west of 

 the Alleghany mountain?. 



