1	Individual flower subtended by a pair of short, hyaline bracteoles at the base		(2)
+	Individual flower without subtending bracteoles		(4)
2 (1)	Annual. Flowers solitary (sometimes 2-3 together) and somewhat distant on the lax inflorescence		Juncus bufonius
+	Perennials. Flowers crowded on a short, simple or branched, terminal or seemingly lateral inflorescence		(3)
3 (2)	Inflorescence seemingly lateral. Leaves basal only, usually reduced to obtuse sheaths		Juncus inflexus
+	Inflorescence terminal. Leaves basal and 1-2 cauline, blade bearing		Juncus compressus
4 (1)	Inflorescence paniculate, seemingly lateral. Flowers mostly in groups of twos or threes		Juncus maritimus
+	Flowers in ± capitate heads		(5)
5 (4)	Inflorescence usually of a single terminal head (very rarely more than 1)		(6)
+	Inflorescence branched, compound, of usually 2-many, terminal heads		(11)
6 (5)	Cauline leaves present, 1-3		(7)
+	Cauline leaves absent		(9)
7 (6)	Stem filiform with 1 cauline leaf. Flowers 3-5(7) in a head, 4-5 mm long. Capsules not exserted; seeds hardly tailed		Juncus benghalensis
+	Stem slender, 1-3-leaved. Flowers usually 8-20 in a head, 6-7 mm long. Capsules ± exserted; seeds tailed		(8)
8 (7)	Anthers c. 1.5 mm long. Capsules ± straight		Juncus membranaceus
+	Anthers 2-3 mm long. Capsules ± arcuate		Juncus concinus
9 (6)	Capsules 6-7.5 mm long, c. twice as long as the perianth. Flowering head usually 2-3 (-4)- flowered		Juncus triglumis
+	Capsules 4-5 mm long, as long as the perianth. Flowering head usually 4-8-flowered		(10)
10 (9)	Lowest subtending bract usually much exceeding the whitish flowering head. Plants greenish, loosely tufted		Juncus leucomelas
+	Lowest subtending bract not or slightly exceeding the brown flowering head. Plants deep green, densely caespitose		Juncus thomsonii
11 (5)	Inflorescence of 2-3(-5) heads, usually of unequal sizes		(12)
+	Inflorescence usually of many heads, ± of equal sizes		(13)
12 (11)	Flowering heads seemingly superposed or shortly stalked. Capsules ± exceeding the perianth, 5-9 mm long; seeds whitish-tailed at the ends		Juncus sphacelatus
+	Flowering heads umbellate, conspicuously stalked, whitish. Capsules not exceeding the perianth, c. 2.5(-3) mm long; seeds not whitish-tailed		Juncus elegans
13 (11)	Plant robust, with 1, sharply tipped cauline leaf, about as long and thick as the stem; basal leaves reduced to sheaths only. Flowers usually 20-40 in each head, c. 2 mm long. Capsules not or hardly exceeding the perianth, less than 20-seeded		Juncus punctorius
+	Plants slender, with 2-10 cauline, linear or filiform leaves; basal leaves with a blade. Flowers 4-12 in each head, 2.5-4(-4.5) mm long. Capsules ± exceeding the perianth, 30-40-seeded		(14)
14 (13)	Stamens 6. Leaves conspicuously septate, terete, curved. Perianth segments lanceolate, acute to subobtuse. Capsules usually oblong-ovoid, abruptly beaked or pyramidate		(15)
+	Stamens 3 (occasionally more). Leaves flat, linear or filiform. Perianth segments linear-lanceolate to subulate, vary acute. Capsules conical with acute tip, beaked		Juncus prismatocarpus
15 (14)	Flowering heads usually semiglobose; smaller. Capsules oblong-ovoid abruptly beaked		Juncus articulatus
+	Flowering head globose, longer. Capsules pyramidate		Juncus kotschyi