| Section 5 » Family Cyperaceae |
Show/Hide Synonym
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| Carex tonsa | < | Carex umbellata | Gleason and Cronquist (1991) | | | Carex tonsa | < | Carex umbellata | Radford, Ahles, and Bell (1968) | | | Carex tonsa | < | Carex umbellata | Wofford (1989) | | | Carex tonsa | = | Carex tonsa var. tonsa | Flora of North America (1993b, 1997, 2000, 2002a, 2002b, 2003a, 2004b, 2005, 2006a, 2006b, 2006c, 2007a, 2009, 2010) | | | Carex tonsa | = | Carex tonsa var. tonsa | Kartesz (1999) | | | Carex tonsa | = | Carex tonsa var. tonsa | | | | Source: Weakley's Flora |
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| Author | (Fernald) Bicknell | |
| Distribution | So far reported from 3 disjunct areas: upper northern Piedmont and northern Mountains, southwestern Mountains (?), and Sandhills and Wake County (?). No doubt more widespread than records indicate, as it is easily overlooked or misidentified. In 2016 Derick Poindexter annotated all specimens of this species group at NCU herbarium; they represent Alleghany, Avery, Cumberland, Hoke, McDowell, Moore, Stokes, and Wilkes counties. Specimens at the SERNEC database from other herbaria are from Ashe, Caldwell, Cherokee, Macon, Richmond, Scotland, Surry, Wake, and Yadkin counties; they need to be double-checked for ID.
Que. to Alb. south to SC, TN, IN, and WI. | |
| Abundance | Apparently uncommon, but probably overlooked. Perhaps fairly common in the northwestern corner of the state. The website editors suggest an S3 State Rank. | |
| Habitat | Dry to xeric rock outcrops, sandhills, sunny woodland ridges, dry roadbanks; soils acidic. | |
| Phenology | Flowering and fruiting April-July. | |
| Identification | In the field it appears as a small tuft of fairly broad leaves with flowering stems usually hidden within, and therefore often passed by. It is very close to C. umbellata but differs in its longer perigynia (3.1-4.7 mm vs. 2.2-3.2 mm). From C. rugosperma, it is told by the leaves smooth on the upper surface (vs. roughened). | |
| Taxonomic Comments | A synonym is C. umbellata var. tonsa.
The genus Carex is the largest in North America, and among the largest in the world. In temperate and boreal regions, Carex is often the dominant or co-dominant ground layer in many habitats. Seeds (achenes) are valuable food for birds and small mammals, while foliage is used by birds and mammals to make nests and as food by mammals. Species of Carex often look vastly different from one another -- spikes erect vs. drooping, tiny inflorescence vs. whopping, culms leafy vs. naked, perigynia beaked vs. beakless, stems densely bunched vs. single, etc. The genus has been divided into many sections (or groups), based on shared characters; some taxonomists have suggested that these be different genera, but that proves unworkable (so far). All Carex share the feature of a perigynium (an outer covering) which completely surrounds the achene (seed). This covering may fit tightly or loosely (like a small bladder), depending on which group or species. Details of perigynia shape, ornamentation, presence and size of beak, number of striations (or veins) are all important ID features. In recent years Rob Naczi and colleagues have stressed the importance of arrangement of perigynia -- whether spiral (3+ ranks) or distichous (2-ranked) -- and have named a number of new species as well as split off some older synonyms. Therefore, RAB's (1968) key, excellent for its time, can only be used in a general way today. Members of some sections of Carex are difficult to key out (notably Ovales, Laxiflorae, Griseae); this is in part due to variation among individuals of a species, or failings of the key. FNA has drawings of most species and some species may be found in two or more places within a key, to acount for variability. New species to NC, and new to science(!), continue to be found in NC. | |
| Other Common Name(s) | None | |
| State Rank | [S3] | |
| Global Rank | G5 | |
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| USACE-emp | | |
