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sandswamp whitetop

Baldwin's beaksedge

Habit Plants perennial, cespitose or solitary, to 100 cm; rhizomes scaly, 3–4 mm thick. Plants perennial, cespitose, 40–100 cm; rhizomes absent.
Culms

arching or erect, leafy-based, distally wandlike, terete, multiribbed.

stiffly erect to ascending, linear, leafy toward base, sharply trigonous, angles scabrid.

Leaves

ascending to spreading, overtopped by scape;

blades linear, proximally flat, 2.5–5 mm wide, apex subulate, trigonous.

shorter than culm;

basal leaves forming strong rosette, shortlinear, flat, 3–5 mm wide, distal more widely spaced, narrower, apex shortacuminate, trigonous.

Inflorescences

terminal, headlike clusters of spikelets, clusters dense, leafy-involucrate;

involucral bracts several, spreading to downcurved, longest 6–13 cm × 5–10 mm, mostly white to midbract, then green, abruptly narrowly linear.

spikelet clusters 1(–2), if 2 then closely set;

terminal cluster mostly dense, hemispheric;

proximalmost leafy bract subulate, much exceeding clusters.

Spikelets

white, ovoid, 5–7 mm;

fertile scales boatshaped, sharply curved-keeled, 5 mm, apex acute.

dark redbrown, ovoid, (4–)5–6 mm, apex acute;

fertile scales ovate, mostly 4–4.5 mm, apex excurvedcuspidate.

Flowers

perianth absent.

bristles 12, reaching to or slightly beyond tubercle tip, antrorsely barbellate.

Fruits

several per spikelet, 1.5–2 mm;

body yellowish to deep brown, tumidly lenticular, broadly obovoid to orbicular or oblate, 1.5 mm, widest at or toward midbody, margins flowing to tubercle;

surfaces with many fine rows of vertical shallow lattices, their contiguous ends making transverse rows of papillae;

tubercle crescent-based, depressed-triangular, 0.5 mm, apex acute.

1–2 per spikelet, 3–3.5(–3.7) mm;

body dark brown with paler center, dull, broadly ellipsoid-lenticular, 2–2.5 × 1.8–2 mm, smooth, margins flowing to tubercle;

tubercle flat, concavely triangular, 0.7–1(–1.2) mm.

2n

= 12.

Rhynchospora latifolia

Rhynchospora baldwinii

Phenology Fruiting late spring–summer. Fruiting spring–fall.
Habitat Sands and peats of bogs in pine savannas and flatwoods Sandy peats in low savannas, pine flatwoods, seeps, and bogs
Elevation 0–200 m (0–700 ft) 0–100 m (0–300 ft)
Distribution
from FNA
AL; FL; GA; LA; MS; NC; SC; TX
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MS; NC; SC
[BONAP county map]
Discussion

A specimen collected near Tullahoma, Tennessee, reported as Dichromena latifolia (A. Gattinger 1901), was later destroyed by fire. I did not see the specimen, nor was a description of it published. Because extant populations of the similar Rhynchospora colorata are just over the border in Alabama, that species is likely to have been the one found by Gattinger.

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

Source FNA vol. 23. FNA vol. 23, p. 237.
Parent taxa Cyperaceae > Rhynchospora Cyperaceae > Rhynchospora
Sibling taxa
R. alba, R. baldwinii, R. brachychaeta, R. breviseta, R. caduca, R. californica, R. capillacea, R. capitellata, R. careyana, R. cephalantha, R. chalarocephala, R. chapmanii, R. ciliaris, R. colorata, R. compressa, R. corniculata, R. crinipes, R. curtissii, R. debilis, R. decurrens, R. divergens, R. elliottii, R. eximia, R. fascicularis, R. fernaldii, R. filifolia, R. floridensis, R. fusca, R. globularis, R. glomerata, R. gracilenta, R. grayi, R. harperi, R. harveyi, R. indianolensis, R. inexpansa, R. inundata, R. knieskernii, R. kunthii, R. macra, R. macrostachya, R. megalocarpa, R. megaplumosa, R. microcarpa, R. microcephala, R. miliacea, R. mixta, R. nitens, R. nivea, R. odorata, R. oligantha, R. pallida, R. perplexa, R. pineticola, R. pleiantha, R. plumosa, R. punctata, R. pusilla, R. rariflora, R. recognita, R. scirpoides, R. solitaria, R. stenophylla, R. thornei, R. torreyana, R. tracyi, R. wrightiana
R. alba, R. brachychaeta, R. breviseta, R. caduca, R. californica, R. capillacea, R. capitellata, R. careyana, R. cephalantha, R. chalarocephala, R. chapmanii, R. ciliaris, R. colorata, R. compressa, R. corniculata, R. crinipes, R. curtissii, R. debilis, R. decurrens, R. divergens, R. elliottii, R. eximia, R. fascicularis, R. fernaldii, R. filifolia, R. floridensis, R. fusca, R. globularis, R. glomerata, R. gracilenta, R. grayi, R. harperi, R. harveyi, R. indianolensis, R. inexpansa, R. inundata, R. knieskernii, R. kunthii, R. latifolia, R. macra, R. macrostachya, R. megalocarpa, R. megaplumosa, R. microcarpa, R. microcephala, R. miliacea, R. mixta, R. nitens, R. nivea, R. odorata, R. oligantha, R. pallida, R. perplexa, R. pineticola, R. pleiantha, R. plumosa, R. punctata, R. pusilla, R. rariflora, R. recognita, R. scirpoides, R. solitaria, R. stenophylla, R. thornei, R. torreyana, R. tracyi, R. wrightiana
Synonyms Dichromena latifolia, R. stellata var. latifolia Phaeocephalum baldwinii
Name authority (Baldwin) W. W. Thomas: Mem. New York Bot. Gard. 37: 86. (1984) A. Gray: Ann. Lyceum Nat. Hist. New York 3: 210. (1835)
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