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FNA | Family List | FNA Vol. 22 | Juncaceae | Juncus

9. Juncus arcticus Willdenow, Sp. Pl. 2: 206. 1799.

Arctic rush

Herbs, perennial, 2--10 dm. Rhizomes long- creeping. Culms erect, 1--3 mm diam. Cataphylls several. Leaves: blade usually absent (present in var. mexicanus). Inflorescences lateral, 3--many-flowered, loose to congested; primary bract barely exceeding to many times longer than inflorescence. Flowers variously pedicellate; bracteoles membranous; tepals chestnut brown or paler, lanceolate, (2.5--)3.3--5.5(--6) mm, margins clear; inner series loosely subtending capsule at maturity; usually slightly shorter, margins scarious to clear, apex acutish to obtuse; stamens 6, filaments 0.2--1.1 mm, anthers 0.9--2.2 mm; style 0.9--1.5 mm. Capsules 3-locular or infrequently pseudo-3-locular, oblate to narrowly ovoid, 3.5--4(--4.5) mm, equal to or exceeding perianth. Seeds dark amber, oblate to ellipsoid, 0.6--0.8 mm.

Varieties 3 7 (3 in the flora): North America; Mexico; South America; Asia.

Numerous entities have been circumscribed and recognized at various nomenclatural ranks by a plethora of authors addressing state or regional floras. In considering the Juncus arcticus-balticus complex as a whole in North America, one is soon confronted with a wide-ranging and obviously polymorphic complex that has not read the literature. It is abundantly clear that the systematics of the group will not be solved on the basis of morphology alone and that resolution of the problem is ripe for molecular investigations.

1 Anthers about as long as filaments; blades absent   9a var. alaskanus
+ Anthers at least 2 times as long as filaments.   (2)
2 (1) Blade-bearing leaves absent   9b var. balticus
+ Distal 1 or 2 leaves with obvious blade   9c var. mexicanus

Lower Taxa


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