Carex sect. Phyllostachyae
in H. G. A. Engler, Pflanzenr. 20[IV,38]: 642. 1909.
Plants cespitose, short-rhizomatous. Culms brown at base, shorter than leaves. Leaves: basal sheaths not fibrous; sheath fronts membranous; sheaths and larger leaves sometimes septate-nodulose; blades V-shaped in cross-section when young, widest at least 2 mm wide, glabrous or papillose. Inflorescences 1 spike or racemose, to 5 spikes; bracts absent; lateral spikes pistillate or androgynous, sometimes some basal; terminal spike androgynous. Proximal pistillate scales green, usually 10+ mm, leaflike. Perigynia erect, veinless or obscurely veined, margins prominently 2-veined, stipitate, lanceolate to oblong-lanceolate, rounded-trigonous to terete, base tapering, apex tapering, beaked, glabrous; beak flattened-triangular, 0.5–6.4 mm, mostly 2+ mm, at least as long as body, entire at orifice. Stigmas 3. Achenes trigonous, as large as or smaller than bodies of perigynia; style deciduous, slightly dilated at base.
Species 10 (10 in the flora).
The level of knowledge of the taxa in Carex sect. Phyllostachyae has grown immensely during the 1990s, and the number of recognized species has doubled during that period. This section has shown the value in delineating taxa of integrating evidence from macromorphology, micromorphology, anatomy, cytology, ecology, genetics. Intriguing questions about inflorescence structure, character homologies, and phylogenetic relationships with the rest of the genus require further study.
In the key that follows, the length of the perigynium beak should be measured from the summit of the achene to the tip of the beak, regardless of whether or not the perigynium tightly envelops the achene.
|1||Widest leaves (4.1–)6–15 mm wide, conspicuously glaucous.||Carex latebracteata|
|1||Widest leaves (1–)2–5.5 mm wide, green or only inconspicuously glaucous.||> 2|
|2||Proximal pistillate scales (2–)2.5–6.5 mm wide, wider than perigynia, surrounding and essentially concealing them; stigmas short, thick, erect or convolute, essentially smooth (papillae minute); staminate flowers 2–4 per spike.||> 3|
|2||Proximal pistillate scales (0.9–)1.2–2.5(–3) mm wide, not more than 1.5 times as wide as perigynia, spreading and not concealing them; stigmas long, slender, flexuous, strongly papillose; staminate flowers (2–)5–25 per spike.||> 5|
|3||Perigynia gradually tapered; beak 1.9–2.9 mm; achenes loosely enveloped by perigynia.||Carex backii|
|3||Perigynia abruptly tapered; beak 0.5–1.6 mm; achenes tightly enveloped by perigynia.||> 4|
|4||Leaves dark green to greenish glaucous, margins white-hyaline, proximal leaf margins and midrib smooth to scabrous; perigynium body papillose on distal 1/3; beak scabrous; achenes 2.5–3 mm.||Carex saximontana|
|4||Leaves dull green to yellowish green, not glaucous, margins green, proximal leaf margins and midrib densely papillose; perigynium body and beak smooth; achenes 2.8–3.5 mm.||Carex cordillerana|
|5||Distal pistillate scales with hyaline margins 0–0.3 mm wide; tallest culms 3.2–9.1 cm; perigynium beak (1.2–)1.4–2.1 mm.||Carex juniperorum|
|5||Distal pistillate scales with hyaline margins 0.3–0.8 mm wide; tallest culms (6–)9–36(–40) cm; perigynium beak (1.5–)2–5.5(–6.4) mm.||> 6|
|6||Perigynia 2–3(–4) per spike, apex abruptly contracted; achenes 1.1–1.3 times as long as wide; staminate scales truncate or rounded.||> 7|
|6||Perigynia (2–)4–9 per spike, apex gradually tapering; achenes 1.2–2.2 times as long as wide; staminate scales obtuse to acute.||> 8|
|7||Staminate portion of terminal spike (4.2–)5.8–14.5 mm; staminate scales 1.1–1.8(–2.1) mm, 0.12–0.25(–0.75) length of staminate portion of terminal spike; perigynium beak 1.6–3.8 mm; basal sheaths brown, lacking red-purple coloration; cataphylls with concave cells.||Carex jamesii|
|7||Staminate portion of terminal spike 3.4–5.6(–6.2) mm; staminate scales (1.9–)2.1–3.3 mm, (0.33–)0.4–0.75 length of staminate portion of terminal spike; perigynium beak 1.4–2.3(–2.5) mm; basal sheaths tinged red-purple; cataphylls with bulging cells.||Carex timida|
|8||Tallest culms less than 0.4 of total plant height, erect; perigynia (7–)7.5–8.9(–10.8) mm; beak (3.6–)4.1–5(–6.4) mm; peduncles usually erect to spreading.||Carex superata|
|8||Tallest culms 0.4–0.9 of total plant height, erect to spreading; perigynia 4.5–8 mm; beak 1.7–4.3 mm; peduncles usually widely spreading to nodding.||> 9|
|9||Staminate portion of terminal spike 3.4–8.6(–10.3) mm; perigynia (4.5–)4.9–5.7(–6.5) mm; beak (1.7–)1.9–2.6(–2.8) mm; achenes (1.8–)2.1–2.5 (–2.6) mm.||Carex willdenowii|
|9||Staminate portion of terminal spike (4–)12.7–25.6 mm; perigynia (5.8–)6.2–7.6(–8) mm; beak (2.5–)2.7–3.7(–4.3) mm; achenes (2.4–)2.6–3(–3.4) mm.||Carex basiantha|