Northern Prairie Wildlife Research Center
Reference:
Marcks, B. G. 1974. Preliminary reports on the flora of Wisconsin. No. 66.
Cyperaceae II -- Sedge Family II. The genus Cyperus -- the
umbrella sedges. Trans. Wisconsin Acad. Sci. 62:261-284.
| Lead | Characteristic | Go To |
| 1 | Spikelets overlapping in dense hemispheric to subglobose spikes. | Lead 2 |
| 1 | Spikelets loosely arranged in subglobose or cylindric spikes, mostly not overlapping. | Lead 3 |
| 2 | Scales with an outwardly curved awn 0.5-1 mm long, conspicuously (5)7- to 9-nerved. | C. aristatus |
| 2 | Scales acuminate, curving outward toward the tip, strongly 3-nerved. | C. acuminatus |
| 3 | Achenes lenticular; styles bifid; scales strongly pigmented with purplish-brown; spikes loosely subglobose. | Lead 4 |
| 3 | Achenes trigonous; styles trifid; scales pale to stramineous or brown; spikes cylindric, with the spikelets pinnately disposed on a more or less elongate rachis. | Lead 5 |
| 4 | Styles exserted ca. 2 mm, persistent, cleft nearly to the base; scales more pigmented near the tip. | C. diandrus |
| 4 | Styles exserted less than 1 mm, deciduous, undivided in the lower 1/3; scales more pigmented near the base. | C. bipartitus |
| 5 | Scales not overlapping in the spikelets, the tip of each one not reaching the base of the scale directly above it (on the same side of the rachilla). | C. engelmannii |
| 5 | Scales overlapping in the spikelets, the tip of each one overlapping with the base of the scale directly above it. | Lead 6 |
| 6 | Scales 1-1.5 mm long, 3- to 5-nerved in the green midstripe, the sides nerveless. | C. erythrorhizos |
| 6 | Scales mostly 2-4.5 mm long, with 7-13 well distributed nerves, these sometimes faint. | Lead 7 |
| 7 | Scales 3-4.5 mm long; achenes less than 1/2 the length of their subtending scales; plants eventually with a hard, cormose base. | C. strigosus |
| 7 | Scales 2-2.5 mm long; achenes over 1/2 the length of the scales; plants not cormose at the base. | Lead 8 |
| 8 | Plants perennial, producing tubers at the ends of underground scaly stolons (these usually evident even if no tubers are collected); rachilla remaining intact as the scales and achenes drop off, eventually the entire rachilla falling off as a whole. | C. esculentus |
| 8 | Plants annual, producing fibrous roots only; rachilla disarticulating between the scales at maturity and falling in segments with the scales and achenes. | C. odoratus |