4. Eriophorum Callithrix Cham. Sheathed Cotton-Grass

Fig. 794

E. vaginatum Torr. Fl. 65. 1824. Not L. E. callithrix Cham.; C. A. Meyer, Mem. Sav. Etrang. 1: 203. 1831.

Plants not stoloniferous; culms tufted, stiff, obtusely triangular, forming tussocks, slender, 8'-2o' tall, leafless, except at the base, rough at the top, bearing 2 or 3 distant inflated sheaths, the upper one usually above the middle. Leaves stiff, filiform, triangular, channeled, slightly rough, shorter than or sometimes overtopping the culm; involucral leaf wanting; spikelet solitary, erect; scales ovate-lanceolate or the lowest lanceolate, acuminate, purple-brown to nearly black, thin; bristles white or red-brown, straight, glossy, 4-5 times as long as the scale; anthers linear; achene obovoid, obtuse, brown, minutely apiculate.

In bogs, Newfoundland to Alaska, south to Massachusetts, Pennsylvania, Wisconsin and Manitoba. Also in Asia. Hare's-tail. Cotton-grass or -rush. Canna-down. Catlocks. Moss-crops. June-Aug.

4 Eriophorum Callithrix Cham Sheathed Cotton Grass 794

5. Eriophorum Opacum (Bjornst.) Fernald. Close-Sheathed Cotton-Grass

Fig. 795

E. vaginatum opacum Bjornst. Grunddr. af. Pit. Lappm. Vaxt. 35. 1856.

E. opacum Fernald, Rhodora 7: 85. 1905.

Loosely tufted, not stoloniferous. Culms slender, terete or nearly so, 1°-2° high, smooth; basal leaves elongated, filiform-channeled; stem-leaves reduced to 2 or 3 close sheaths, the lower one sometimes with a short blade; spikelet solitary, erect; scales thin, ovate-lanceolate or the inner ones linear-lanceolate, acuminate; bristles white or brownish; achene obo-vate-oblong, apiculate.

Bogs, Maine and Massachusetts to Ontario, Alberta, the Yukon Territory and British Columbia. Also in Europe and Asia. Summer.

5 Eriophorum Opacum Bjornst Fernald Close Sheathed 7955 Eriophorum Opacum Bjornst Fernald Close Sheathed 796

6. Eriophorum Gracile Koch. Slender Cotton-Grass

Fig. 796

E. gracile Koch; Roth, Catal. Bot. 2: 259. 1800. E. triquetrum Hoppe, Taschenb. 1800: 106. 1800.

Culms slender, smooth, nearly terete, spreading or reclining, 20 long or less. Leaves triangular-channeled, the basal ones mostly wanting at flowering time, those of the culm 2 or 3, the upper one with a blade shorter than its sheath, 1 3/4 long or less; involucral leaf about 1/2' long; spikelets 2-4, rarely 6, the slender peduncles pubescent, mostly less than 1' long; scales ovate, grey to nearly black, acutish, the midvein prominent; achenes obovate-oblong, about 1" long; bristles bright white, 1/2'-3/4 long.

In bogs, Quebec to British Columbia, New York, Pennsylvania, Iowa, Nebraska, Colorado and California. Also in Europe and Asia. June-Aug.

7. Eriophorum Tenellum Nutt. Rough Cotton-Grass

Fig. 797

Eriophorum tenellum Nutt. Gen. Add. 1818.

E. paucinervium A. A. Eaton, Bull. Torr. Club 25: 341. 1898.

Culm slender, stiff, obtusely triangular, rough on the angles above, 1°-21/2° tall, the sheaths all blade-bearing. Leaves narrowly linear, 1" wide or less, triangular-channeled, rough-margined, the upper longer than its sheath; involucral leaf commonly only 1, stiff, erect; spikelets 3-8, capitate or subumbellate, the longer-peduncled ones drooping; scales ovate or oblong, obtuse or subacute, pale yellow to brown, the midvein rather strong, often with a weaker nerve on each side; bristles numerous, bright white, 8"-12" long, 4-6 times as long as the scale; achene linear-oblong, acute, pointed, 1 1/2" long.

In bogs, Newfoundland to Hudson Bay, New Jersey, Pennsylvania and Illinois. Formerly confused with the next preceding species. June-Sept.

7 Eriophorum Tenellum Nutt Rough Cotton Grass 797