Carex section Laxiflorae of Arkansas

(revised October 1. 2012)

(Taxonomy of species marked with an asterisk * matches the "Checklist of the Vascular Plants of Arkansas", a document of the Arkansas Flora Committee, version 9.0, January 18, 2003).

Naczi, et al. (2002) provide a key to the Carex section Laxiflorae in the western hemisphere. I hope to modify my current key and add it here shortly. They describe Carex kraliana, a new species known (in Arkansas) from a few sites on Crowley's Ridge. This paper started a shift as described below.

Key to the Laxiflorae of Arkansas

(Modified from Naczi, et al. 2002)

Keys do not easily made in html code, so this one may appear a bit awkward. Perhaps eventually I'll figure out a way that will work on a variety of browsers. For now, I'll pair up the numbers with a variety of symbols to make the key pairs easier to match.

*1. Bract blades of distal (top) lateral spikes lanceolate or narrowly lanceolate, wider than the spikes and concealing them when viewed from abaxial (lower) surface, widest bract blade (per plant) of distal-most lateral spike (3.0-) 3.2 - 8.3 mm wide ....... **2

**2. Widest leaf or bract blade 1.3 - 3.8 (-5.0) cm wide; pistillate scales from proximal (lower) portions of spikes awnless (sometimes mucronate), with truncate bodies; perigynia (1.6-) 1.7 - 1.9 wide ....... C. albursina Sheldon

**2. Widest leaf or bract blade 0.5 - 1.1 cm wide; pistillate scales from proximal (lower) portions of spikes awned, with acute bodies; perigynia 1.3 - 1.7 (-1.8) wide ....... C. kraliana Naczi & Bryson

*1. Bract blades of distal (top) lateral spikes linear, narrower than the spikes and not concealing them when viewed from abaxial (lower) surface, widest bract blade (per plant) of distal-most lateral spike 0.5 - 3.4 mm wide ....... **3

**3. Shoot bases purplish, with purplish coloration ranging from slight tinge of brown background in basal 5 mm of shoots to strong staining that obscures the brown background and extends 14 cm high ....... C. gracilescensSteudel

**3. Shoot bases brownish or whitish, with purplish color completely absent ....... ***4

***4 need to complete key. See Naczi, et al. (2002) for complete key

Today, March 9, starts a breakthrough in my work in Arkansas Carex. I start a transfer of my basic info from a hard copy volume to the web based info. The need is obvious; to disperse the info easily to as many people as possible. This work is likely to become my final product in my efforts to produce a book on Arkansas Carex by 2011. Time, I'm afraid, is running out! The Arkansas Flora Committee plans to produce a flora of Arkansas about that time, or earlier. My efforts here are to present two types of info: 1) the info you need to identify Arkansas sedges and 2) info that would not be appropriate for a state flora. That is, I can include details here that will not be available on the web. In like manner, the flora will have details which I do not plan to present here, such as details on the anatomy of each species. The two works will have some overlap, but will compliment each other. I'm posting this today, like much of this web site, in a preliminary fashion. Preliminary to what? My final product of 2011. I expect to add more detail to this page shortly (tonite or in the next few days).

The section Laxiflorae contains "about 25 species in eastern North America (17 in [the southeastern United States], one in the western United States, and a few in eastern Asia (Tucker 1987) and several taxa in Arkansas, including subspecies. These woodland plants "are caespitose and bear conspicuouly two-nerved perigynia" (op. cit.). "An aneuploid series is evident in these southeastern representatives of the section for which chromosome numbers have been reported" (ibid). Carex striatula and C. laxiflora are myrmecochorous (Gaddy 1986).

* Carex albursina Sheldon

[synonym = C. laxiflora Lam. var latifolia]

This species occurs only in mountain counties in Arkansas and appears more widespread in the Ozarks than the Ouachitas. Habitats typically include deep valleys and mesic north facing slopes where this sedge can be found with similar species, C. laxiflora and C. blanda, as well as creek terraces. Deer sometimes will nibble plants so heavily that finding a good herbarium specimen becomes difficult for collectors. Arkansas material tends to be somewhat narrow-leaved for the species; it also has the diagnostic "lack of serrations on the sheath margins and the more or less truncate pistillate scales" (Reznicek, pers. commun.). "Ranges from Quebec to Vermont to Minnesota, south to Virginia, Tennessee, and Arkansas" (Steyermark 1963).

* Carex blanda Dewey

[synonym = C. laxiflora Lamarck var. blanda (Dewey) Boott]

FAC?. A common to abundant weedy species which spreads rapidly in the Ozarks, this plant is scattered statewide. Still missing from 15 counties, but expected in all. It thrives in a variety of habitats but shows an affinity for moisture. Habitats include roadsides, homesites, fields, springs, seeps, floodplains, mesic deciduous woods in valleys, and north facing slopes. Woodland Sedge readily invades disturbed areas with reasonable soils. With the use of a hand lens or scope at 10x, the bent beaks of this plant make it easy to identify even in the field, once recognized. Other Arkansas carices have bent beaks, but none with the beak bent so abruptly in the section Laxiflorae. The novice might confuse it with C. granularis, but the latter has perigynia in spikelets that form elongated clusters reminicent of C. caroliniana, while C. blanda spikelets do not form into elongated structures. Ranges from Wyoming, south and eastward to Texas and New Mexico, east to northern Florida and north to Quebec, Ontario, and North Dakota (Jones and Bryson 1993). n=18, 19, 20, 21, 22 (Tucker 1987).

Return to Sedgehead dot com.

* Carex crebriflora Wiegand

Probably FAC, but not addressed by U. S. Corp of Engineers. This early species seems to bloom in April to early May. The nearly uniformly green plants love streamside zones in small drainages to small perennial streams. Locally scattered to occasional, usually not in large numbers but widepread. Recent collections indicate it is likely widespread in the West Gulf Coastal Plain in both Arkansas and Louisiana, but its discovery in Arkansas is only a few years old. Searches in 1996 added 3 counties in a few hours, but the author has yet to find it more than a chain (66 feet) from a stream and usually within a few meters. While not covering huge upland acreages, I suspect it is widespread and common in south Arkansas and in no need of tracking by the state heritage program, but this has yet to be proven by numerous sightings and collections. C. crebriflora mimics C. blanda in general form. The straight beaked perigynia tend to be clustered in more tightly packed (but still loosely arranged) spikelets for laxiflorian sedge. The 3-4 clusters of perigynia at the tip of the stem make this sedge stand out as something different from others in the section.

* Carex gracilescens Steudel

[synonym = C. laxiflora Lamarck var. gracillima (Boott) Robins & Fernald]

Demaree (1943) reported this plant for Arkansas. Reznicek (pers. commun. 1995) pointed out two Naczi specimens from Howard County (1917, 1926 MICH) and a Hyatt specimen from Baxter County [add number]. Based on its habitat and distribution in Missouri, this species should occur on "mesic to dry upland forests, on calcarous substrates" in northern Arkansas on the Salem plateau especially; this plant differs from C. blanda (which has stem bases white to light brown) by its dark reddish purple "stem and lowermost leaf sheath bases" (Yatskievych 1999). Further study of this plant in Arkansas is needed. "Ranges from Vermont and Quebec to Ontariio and Wisconsin, south to Alabama and Texas" Steyermark (1963). n=20 (Tucker 1987).

Carex kraliana Naczi & Bryson

[formerly recognized in Arkansas as Carex laxiflora Lamarck var. serrulata Fernald]

Newly described. More on this one later. From Crowley's Ridge. See Naczi, et al. (2002).

* Carex laxiflora Lamarck

[not including Carex laxiflora Lamarck var. serrulata Fernald; synonyms include C. anceps Muhl. and C. patulifoliaDewey]

NI on the species level. I have recorded this variety in Baxter County. Additional study is needed. It occurs on interbedded limestone and sandstone on north facing slopes in deciduous woods. Loose-flowered sedge recolonizes disturbed sites only very slowly if its mesic habitat persists (or is created), but seems to thrive on the natural disturbance of rocky talus slopes. Orzell and Bridges (1987), in recording the species for Van Buren County, mention "the habitat and associates for this species are the same as... [those of] C. laxiculmis"; I concur, but suspect this species likes slightly more mesic sites. Reznicek (pers. commun.) states Hyatt no.?? of Loose-flowered sedge is unusual in having small bracts and wide leaves, but occasional specimens are like this. Ants, Aphaenogaster rudis Emery and Crematogaster lineolata Say, disperse the perigyina of Loose-flowered Sedge, which has small elaiosomes (Gaddy 1986). [C. laxiflora] is rare and reaches its southern limit in Arkansas" (Reznicek, pers. commun.). [AAR would like more material]. n=20 (Tucker 1987).

* Carex striatula Michaux

[synonyms include C. ignota Dewey, C. styloflexa Buckley var. remotifolia Wiegand, and C. laxiflora Lamarck var. michauxii Bailey]

Orzell and Bridges (1987) reported that A. A. Reznicek determined G. M. Merrill 215, SMU as this species. This collection is the first [published] for the species for Arkansas and the "most northwestern record of the species", and it "would likely occur on the Coastal Plain of Arkansas" (ibid). 1985 and 1986 collections from Ashley County at UAM come from ridgetops and rich, wooded slopes above creeks on sandy soil. This species seems absent from roadsides and \probably does not tolerate or compete well at disturbed sunny sites. Recent (1995-19989) herbarium searches continue to expose scattered Arkansas records. Fresh material was noted as "blue-green" on one voucher; Bryson (pers. commun. 1994) says the leaves are rough and glaucous. From the author's recent (1995 and 1996) experience in the West Gulf Coastal Plain, especially in Louisiana, this plant should occur in habitat similar to C. digitalis var. macropoda throughout south Arkansas. Collections seem most easily determined by the white base to the stems, often 3-4 inches of the plant and often shaded by leaf litter; this character seems to be consistent and distinctive, even though it is subjective if one trys to describe it. In fresh material, especially, the white base stands out clearly. C. striatula also occurs in Georgia, and North and South Carolina [verify rest of range].

* Carex styloflexa

Reported for Arkansas by Sundell (1986). I annotated his 3 vouchers as C. striatula; E. B. Smith of UARK also annotated one of these this way. This species is difficult to separate from C. striatula and C. crebriflora using keys alone. The task is much easier when a series of specimens is on hand for comparison. I have annotated specimens from NLU (Neva Co.) and VDB (Ashl Co.) as this species recently.


Hyatt, Philip E. 1999. Arkansas Carex (Cyperaceae): a preliminary list [or some such title]. Sida. Correct citation to be added later.

Naczi, Robert F. C., Charles T. Bryson, and Theodore S. Cochrane. 2002. Seven new species and one new combination in Carex(Cyperaceae) from North America. Novon 12: 508-532.

Smith, Edwin B. 1994. Keys to the Flora of Arkansas. The university of Arkansas Press. Fayetteville. 363 pages.

Yatskievych, George. 1999. [revised Missouri flora volume 1]