Flora of North America species comparison

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Carex viridula subsp. viridula

Carex sect. Ceratocystis
Photo is of parent taxon

green sedge, greenish sedge, little green sedge
Habit Plants cespitose or not, short-rhizomatous.
Culms

brown at base.
Leaves

basal sheaths not fibrous;

sheath fronts membranous;

blades sparsely septate-nodulose, usually V-shaped in cross section when young, glabrous.
Inflorescences

racemose, with 2–6 spikes;

proximal nonbasal bracts leaflike, long-sheathing, shorter or longer than diameter of stem;

lateral spikes pistillate, rarely distal androgynous, larger spikes with not more than 40 perigynia, dense, pedunculate, prophyllate;

terminal spike staminate or, occasionally, androgynous.
Perigynia

ascending, spreading, or reflexed, proximal and middle perigyinia separated by internodes less than 1/10 their length, yellow-brown to brown, strongly veined on faces, slightly stipitate, obovoid or, rarely, narrowly ovoid, rounded-trigonous, less than 10 mm, base tapering to rounded, apex abruptly contracted or, rarely, tapering to beak, glabrous;

beak bidentate, teeth less than 0.5 mm.
Achenes

trigonous, 1–2 mm, smaller than bodies of perigynia;

style deciduous.
Proximal

pistillate scales with apex obtuse, acute, or cuspidate.
Stigmas

3.

Carex viridula subsp. viridula

Carex sect. Ceratocystis
Distribution
from USDA
North America; Europe; Asia
[BONAP county map]
Circumboreal; north and south temperate regions in North America; Europe; Asia; Australia
Discussion

Varieties 1 (1 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 7 (5 in the flora).

Sterile hybrids regularly form among species of Carex sect. Ceratocystis. These include Carex hostiana × C. flava (= C. ×xanthocarpa Dégland), C. hostiana × C. viridula (= C. ×fulva Goodenough), C. flava × C. viridula (= C. ×ruedtii Kneucker), and C. cryptolepis × C. viridula.

Some taxa included within C. viridula have been treated as species. Hybrids that form among these taxa (subspecies and varieties) are partially fertile, indicating that they have not diverged widely enough to be reproductively isolated. Their morphologic variation patterns also overlap (W. J. Crins and P. W. Ball 1989).

Carex sect. Ceratocystis is most closely related to sect. Spirostachyae (Drejer) L. H. Bailey, an Old World group with three introduced species in North America. These sections often have been combined as sect. Extensae Fries (a later name), but several characteristics distinguish the sections (W. J. Crins and P. W. Ball 1988).

In the keys that follow, curvature of the perigynium beak is measured as the angle formed by the junction of a straight line through the beak with a straight line through the abaxial portion of the perigynium body. Perigynium length includes the body and beak, unless noted otherwise.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Plants not cespitose, with short, stout, horizontal rhizomes; inner band of bract sheaths with convex projections to 3.2 mm; scales dark brown with conspicuous white borders; perigynia ascending.
C. hostiana
1. Plants cespitose; inner band of bract sheaths truncate or concave; scales yellowish green to reddish brown with inconspicuous hyaline borders; perigynia (in fruit) spreading or reflexed.
→ 2
2. Perigynia spreading; beak straight or forming angle less than 25° with body; ligules on distal cauline leaves usually obsolete.
C. viridula
2. Proximal perigynia reflexed; perigynium beak forming angle usually greater than 20° with body; ligules on distal cauline leaves truncate or rounded, well developed.
→ 3
3. Pistillate scales yellowish green, similar in color to perigynia.
→ 4
3. Pistillate scales brownish, contrasting with yellowish green perigynia.
→ 5
4. Tallest culms 25–50 cm; proximal pistillate spike bracts 1.5–4 times as long as inflorescences; peduncles of staminate spikes 0.2–0.5 length of staminate spikes; perigynium beak smooth; achenes 1–1.2 mm wide.
C. cryptolepis
4. Tallest culms 65–125 cm; proximal pistillate spike bracts 0.5–1.3(–1.9) times as long as inflorescences; peduncles of staminate spikes mostly 0.7–2.5 length of staminate spikes; perigynium beak usually sparsely scabrous; achenes 1.2– 1.5 mm wide.
C. lutea
5. Staminate spikes sessile or short-pedunculate, peduncles usually less than 5 mm; cauline leaves usually nearly as long as culms; perigynium beak conspicuously scabrous, usually more than 1.6 mm.
C. flava
5. Staminate spikes on peduncles usually more than 4.5 mm; cauline leaves 0.5 times as long as culms or less; perigynium beak weakly scabrous, usually less than 1.7 mm.
C. viridula
Source FNA vol. 23. FNA vol. 23. Author: William J. Crins.
Parent taxa Cyperaceae > Carex > sect. Ceratocystis > Carex viridula Cyperaceae > Carex
Sibling taxa
C. viridula subsp. brachyrrhyncha, C. viridula subsp. oedocarpa, C. viridula var. elatior, C. viridula var. saxilittoralis, C. viridula var. viridula
Subordinate taxa
C. cryptolepis, C. flava, C. hostiana, C. lutea, C. viridula
Name authority unknown Dumortier: Fl. Belg., 147. (1827)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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