Rhynchospora compressa |
Rhynchospora microcephala |
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flatfruit beaksedge |
smallhead beaksedge |
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Habit | Plants perennial, cespitose, 70–100(–150) cm; rhizomes absent. | Plants perennial, cespitose, 30–90 cm; rhizomes absent. |
Culms | erect to ascending, leafiest at base, triangular, slender, somewhat stiff. |
arching or erect, leafy, nearly terete, multiribbed, slender. |
Leaves | exceeded by culm; basal blades crowded, spreadingexcurved, distal ascending, linear, proximally flat, 3–5 mm wide, apex trigonous, shortsubulate. |
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Inflorescences | spikelet clusters 3–5, compact, the proximalmost widely spaced, turbinate or lobed to hemispheric; leafy bracts setaceous, mostly overtopping clusters. |
spikelet clusters 2–6, mostly widely spaced; clusters dense, hemispheric to mostly spheroid, 0.5–1 cm thick. |
Spikelets | redbrown, broadly ovoid, 3–3.5(–4) mm, apex acuminate; fertile scales broadly ovate to ± orbiculate, 2–2.5(–3) mm, apex rounded to notched, midrib included or shortexcurrent. |
dark redbrown to dark brown, lanceovoid, (2–)2.5–3.5(–4) mm, apex acute; fertile scales elliptic, 2–3 mm, apex acute, midrib shortexcurrent or not. |
Flowers | perianth bristles 6, reaching from fruit midbody to tubercle, antrorsely barbellate. |
perianth bristles 6, reaching tubercle tip, retrorsely barbellate. |
Fruits | 1–2 per spikelet, (2–)2.5–2.8(–3) mm; body brownish, broadly obovoid to nearly orbicular, 1.5–2 × 1.5–2 mm; surfaces strongly transversely wavyrugose, intervals rows of vertical, rectangular alveolae; tubercle conic-subulate, basal rim flaring above short neck on achene. |
1 per spikelet, 2.5–3 mm; body pale brown with light center, lenticular, obovoid distal to stipe, 1.1–1.5 × 0.9–1.1 mm, margins pale, wirelike, surfaces slick; tubercle triangularsubulate, 0.9–1.2(–1.5) mm, at least 0.5 mm wide at base. |
Principal | leaves overtopped by culm; blades linear, proximally flattened, 1–3 mm wide, apex tapering, trigonous. |
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Rhynchospora compressa |
Rhynchospora microcephala |
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Phenology | Fruiting spring–fall. | Fruiting summer–fall. |
Habitat | Moist sands and peats of pine flatwoods, bog margins, savannas | Sands and sandy peats of savanna swales, pineland seeps, bogs, ditches, pond shores and banks |
Elevation | 0–100 m (0–300 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; FL; GA; LA; MS; SC |
AL; DC; DE; FL; GA; LA; MD; MS; NC; NJ; SC; VA; West Indies (Cuba)
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Discussion | Rhynchospora compressa is very closely akin to R. recognita and even coarser; inflorescence clusters are about as bristly and fertile scales blunter than those in R. recognita. It is less inclined to have an excurrent midrib, and the fruit is flatter. Both species often produce sterile spikelets, sometimes comprising an entire inflorescence. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23. | FNA vol. 23, p. 213. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Phaeocephalum compressum, R. cymosa var. compressa | R. axillaris var. microcephala, R. cephalantha var. microcephala |
Name authority | J. Carey ex Chapman: Fl. South. U.S., 525. (1860) | (Britton) Britton ex Small: Fl. S.E. U.S., 195. (1903) |
Web links |