1	Mid-stem and proximal leaves distinctly petiolate, broadly lanceolate to ovate or deltate		(2)
+	Mid-stem and proximal leaves sessile to shortly petiolate; blades elliptic, ovate, lanceolate, linear, or linear-lanceolate		(8)
2 (1)	Leaf blade bases cordate to truncate (rarely abruptly rounded)		9 Stellaria cuspidata
+	Leaf blade bases round or cuneate		(3)
3 (2)	Flowers large, usually 10 mm or more diam.; petals usually exceeding sepals		(4)
+	Petals equaling or shorter than sepals, or absent; flowers less than 10 mm diam		(5)
4 (3)	Sepals obtuse to acute, 3.5-6 mm		27 Stellaria pubera (in part)
+	Sepals acuminate, (5-)7-10(-12) mm		6 Stellaria corei
5 (3)	Flowers solitary in axils of mid and distal stem leaves		22 Stellaria obtusa (in part)
+	Flowers several in foliaceous terminal cymes		(6)
6 (5)	Sepals 5-6.5 mm; stamens 8-10; seeds 1.1-1.7 mm; tubercles taller than broad, apex acute		20 Stellaria neglecta
+	Sepals usually 3-5(-6) mm; stamens 1-5(-8); seeds 0.4-1.3 mm; tubercles usually broader than tall, apex usually obtuse		(7)
7 (6)	Stamens 3-5(-8); sepals 4.5-5(-6) mm; seeds 0.9-1.3 mm diam.; petals usually present; plants usually green		19 Stellaria media
+	Stamens 1-3 or absent; sepals 3-4 mm; seeds mostly 0.5-0.9 mm diam.; petals usually absent; plants usually yellowish green		23 Stellaria pallida
8 (1)	Inflorescences, or flowers when solitary, in axils of foliage leaves on mid or distal stem		(9)
+	Inflorescences with most flowers terminal, either several in bracteate inflorescence or solitary on long-ascending pedicels		(18)
9 (8)	Petals equaling or longer than sepals		(10)
+	Petals shorter than sepals, or absent		(13)
10 (9)	Sepals narrowly lanceolate-triangular, prominently 3-veined, margins straight		7 Stellaria crassifolia (in part)
+	Sepals lanceolate to ovate-lanceolate, 1- or obscurely 3-veined, margins convex		(11)
11 (10)	Seeds prominently papillate, papillae taller than broad; sepals pubescent		25 Stellaria parva
+	Seeds smooth, rugose, or shallowly tuberculate, not papillate; sepals glabrous		(12)
12 (11)	Leaf blades succulent, elliptic to elliptic-lanceolate, 4-15 × 1-5 mm		14 Stellaria humifusa
+	Leaf blades not succulent, linear to linear-lanceolate, 27-35 × 2-3 mm		26 Stellaria porsildii
13 (9)	Plants forming dense cushions, mid and distal stem internodes shorter than leaves		(14)
+	Plants creeping to straggling or ascending, sometimes forming mats, but not forming cushions, internodes equaling or longer than leaves		(15)
14 (13)	Stamens 5; petals present, deeply divided into 2 narrowly elliptic lobes		15 Stellaria irrigua
+	Stamens 10; petals absent		10 Stellaria dicranoides
15 (13)	Leaf blades narrowly elliptic to lanceolate, oblanceolate, or linear		(16)
+	Leaf blades broadly elliptic to ovate		(17)
16 (15)	Flowers solitary in distal leaf axils		11 Stellaria fontinalis
+	Flowers in axillary inflorescences in mid and distal leaf axils		2 Stellaria alsine
17 (15)	Sepals obtuse at apex with ± obscure veins; styles shorter than 0.5 mm, curled; capsules globose to broadly ovoid		22 Stellaria obtusa (in part)
+	Sepals acute to acuminate at apex with 3 prominent veins; styles ca. 1 mm, spreading to ascending; capsules ovoid to ovoid-ellipsoid		8 Stellaria crispa
18 (8)	Bracts scarious or with scarious margins		(19)
+	Bracts or subtending leaf blades without scarious margins		(26)
19 (18)	Capsules ca. equaling or shorter than sepals		(20)
+	Capsules longer than sepals		(22)
20 (19)	Plants annual		21 Stellaria nitens
+	Plants perennial		(21)
21 (20)	Plants compact; stems ascending, 3-10(-20) cm; petals equaling or shorter than sepals		1 Stellaria alaskana
+	Plants coarse; stems straggling with erect branches, 20-60 cm; petals 1.5-2 times as long as sepals		24 Stellaria palustris
22 (19)	Inflorescences subumbellate; petals absent		29 Stellaria umbellata
+	Inflorescences cymose or flowers solitary; petals present		(23)
23 (22)	Plants delicate, creeping, often forming mats; flowers solitary and axillary or in small, few-flowered, leafy cymes; leaf blades variable in shape, midribobscure		7 Stellaria crassifolia (in part)
+	Plants not with the above combination of characters; leaf blades with prominent midrib		(24)
24 (23)	Leaf blades linear-elliptic, broadest at middle or distally; angles of stems and/or margins of leaf blades minutely papillate-scabrid (30×)		17 Stellaria longifolia
+	Leaf blades lanceolate to linear-lanceolate, broadest proximally; angles of stems and/or margins of leaf blades not papillate-scabrid (soft hairs of cilia may be present)		(25)
25 (24)	Sepals narrowly triangular or lanceolate, margins straight, veins 3, forming prominent ridges; seeds coarsely rugose in concentric rings; plants coarse; stems ascending, straggling; inflorescences muchbranched, many-flowered		12 Stellaria graminea
+	Sepals lanceolate to ovate-lanceolate, margins convex, veins 1-3, not forming ridges; seeds shallowly tuberculate to smooth; stems erect to straggling; flowers solitary or inflorescences few-flowered		18 Stellaria longipes (in part)
26 (18)	Flowers 20-30 mm diam.; petals 8-14 mm, longer than sepals; leaf blades narrowly lanceolate, 4-8 cm, apex acuminate		13 Stellaria holostea
+	Plants not having the above combination of characters		(27)
27 (26)	Leaves widest at or above middle		(28)
+	Leaves widest towards base		(31)
28 (27)	Plants glandular-puberulent; pedicels arcuate, pushing capsule into substrate; seeds 3-6, ca. 2.5 mm diam		3 Stellaria americana
+	Plants eglandular; other characters not as above		(29)
29 (28)	Sepals narrowly lanceolate-triangular; plants creeping, forming mats usually shorter than 5 cm		7 Stellaria crassifolia (in part)
+	Sepals ovate to ovate-triangular; plants with diffusely branched or ascending flowering stems taller than 5 cm		(30)
30 (29)	Petals 4-8 mm, conspicuous, white; sepals 3.5-6 mm		27 Stellaria pubera (in part)
+	Petals shorter than 3 mm, inconspicuous, white or translucent; sepals2-3(-4) mm		4 Stellaria borealis (in part)
31 (27)	Plants straggling to scandent; stems to 60 cm; leaf blades ovate to ovate-lanceolate, 10-45 × 4-20 mm; inflorescences terminal leafy cymes		16 Stellaria littoralis
+	Plants not having the above combination of characters		(32)
32 (31)	Sepals 2-3(-4) mm; open flowers less than 5 mm diam.; petals not exceeding sepals, inconspicuous or absent		(33)
+	Sepals 3.5 mm or longer; open flowers 5 mm or more diam.; petals equaling or exceeding sepals, conspicuous		(34)
33 (32)	Capsules broadly ovoid to globose, to 1.5 times as long as broad; styles less than 1 mm; sepals in open flowers less than 2.5 mm, veins obscure (rarely 1)		5 Stellaria calycantha
+	Capsules ovoid, more than 1.5 times as long as broad; styles longer than 1 mm; sepals in open flowers more than 2.5 mm with 1-3 prominent veins		4 Stellaria borealis (in part)
34 (32)	Sepals 4.5-6 mm; leaf blades ovate to broadly lanceolate, coriaceous, apex spinous; capsules equaling sepals		28 Stellaria ruscifolia
+	Sepals 3.5-5 mm; leaf blades lanceolate to linear-lanceolate, not strongly coriaceous, apex acute to acuminate, not spinous; capsules 1.5-2 times as long as sepals		18 Stellaria longipes (in part)