CYPERACEAE (SEDGE FAMILY) 



181 



b. Achenes trianpriilar or turg^id ; style 3-cleft g. 

 g. Acheiies reg'ularly reticulate or cross-lined. 



Spikelets flattened, O-y-tlowered ; the thin scales 2-3-ranked , 

 Spikelets terete ; the scales many-ranked. 



Upper sheaths loose, with white scarious tips ; achenes 

 finely cross-lined between the strong ribs .... 

 Upper sheaths close and lirm, not scarious ; achenes distinctly 

 reticulate. 

 Tubercle conic-subulate, much smaller than the achene 

 Tubercle cap-shaped, as large as the achene 

 g. Ach«nes smooth or papillose, not regularly reticulate h. 

 h. Tubercle depressed, as broad as high or broader. 



i. Achenes white 



i. Achenes yellow, brown, or black j. 

 j. Achenes smooth. 



Tubercle flattened and closely covering the top of the 



black achene 



Tubercle short-conic, constricted below, narrower than 



the olive-brown achene 



j. Achenes pai>illose-roughened. 



Achene with prominent keel-like angles . . . . 



Achene with the angles not keeled. 



Tips of the upper sheaths dark -girdled ; achenes 



golden-yellow or orange-brown (in age drab), 



conspicuously papillose-roughened, plump, with 



rounded angles. 



Culms fihform, 4-angled 



Culms flattened 



Tips of the upper sheaths whitish : achenes whitish- 

 yellow, minutely roughened, with distinct angles 

 K. Tubercle long-conic, higher than broad. 



Tubercle clearl^v distinct from the achene. 

 Tubercle conic-subulate, much narrower than the plump 

 achene. 



Bristles exceeding the achene 



Bristles wanting (24) E. 



Tubercle conic-deltoid, nearly as broad as the compressed 



achene 



Tubercle seemingly confluent with the achene 



13, E. acicularia. 



14. F. Wnl/ii. 



15. £. toriilis. 



16. E. tuberculosa. 



17. F. Torreyana. 



18. E. meJanocarpa. 



19. E. alMda. 



20. E. iricostata. 



21. E. tenuis. 



22. E. acuminata. 



23. E. nitida. 



24. E. intermedia, 

 intermedia, v. Hahereri, 



25. E. Macounii. 



26. E. roHieUaia. 



238. E. interstincta. 



1. E. interstincta (Vahl.) R. & S. Culms large and stout 

 (0.5-1 m, high), knotted as if jointed by many cross-partitions ; 

 basal sheaths often leaf-bearing ; spikelets 2-4 cm, long ; scales 



in several ranks, pale, with scarious mar- 

 gins ; achene with transversely linear-rec- 

 tangular reticulation and a conical-beaked 

 tubercle ; bristles 6, rigid, or wanting. {E. 

 eqiiisetoides Torr.) — Shallow water, Mass. 

 to Fla., w. to Mich, and Tex. (W. I., 

 S. A.) Fig. 238. 



2. E. quadrangulata (Michx,) R. & S. 

 Similar ; culm continuous and sharply 

 4-angled; spikelet 2-6 cm. long ; achene finely reticulated, 

 with a conical flattened distinct tubercle. {E. mutata 

 Britton, not R. & S.) — Shallow water, Ct. to Mich., and 

 southw., rare. Fig. 239. 



3. E. Robbinsii Dakes. Flower-bearing 

 culms exactly triangular, rather slender, 



erect (2-7 dm. high), also producing tufts of capillary abortive 

 stems or line leaves, which float in the water ; sheath obliquely 

 truncate ; spikelet 1-2.5 mm. long ; scales only 

 3-9, feic-ranked, convolute-clasping the long 

 flattened joints of the axis, lanceolate, with thin 

 scarious margins; achene oblong-obovate. tri- 

 angular, minutely reticulated, about half the 

 length of the bristles, tipped with a flattened awl-shaped tubercle. 

 — Shallow water, X. B. to Fla., w, to Mich, and Ind, Fig. 240. 

 4, E. ochreata (Nees) Steud, Similar in habit to the next ; 

 the capillary culms 3-30 cm. high ; spikelets 2-6 mm. long ; scaU.^ 



239. E. quadrangulata. 



240. E.Eobbinsii. 



241. E. ochreata. 

 Spikelet x 2%. 

 Achene x lu. 



