1	Ovary 4--10-loculed, with axile placentation; berry indehiscent; seeds sometimes with a spongy (never succulent) aril on 1 side.		(2)
+	Ovary 1-loculed with parietal placentation; berrylike capsule dehiscing irregularly; seeds with a succulent aril.		(9)
2 (1)	Rhizome creeping, elongate, slender, 2--5 mm thick; seeds without aril, funicle not swollen.		(3)
+	Rhizome 8--45 mm thick; seeds ± enveloped by whitish green, spongy aril formed by swollen funicle.		(5)
3 (2)	Leaves usually 6--8; outer tepals oblong-lanceolate to ovate-lanceolate, 10--25(--30) mm wide		20 Paris verticillata
+	Leaves usually 4; outer tepals narrowly lanceolate, 3--9 mm wide.		(4)
4 (3)	Leaves oblong-lanceolate or ovate-elliptic; outer tepals reflexed, 3--5 mm wide		21 Paris bashanensis
+	Leaves broadly obovate or ovate; outer tepals spreading horizontally, 5--9 mm wide		22 Paris quadrifolia
5 (2)	Leaves 9--10		19 Paris dulongensis
+	Leaves 4--6.		(6)
6 (5)	Leaves wrinkled, obovate, 10--15 × 6.3--10 cm, basally rounded		18 Paris rugosa
+	Leaves not wrinkled.		(7)
7 (6)	Leaves elliptic or oblanceolate, base subcuneate		17 Paris vaniotii
+	Leaves oblong, ovate- or obovate-oblong, or oblong-lanceolate, base shallowly cordate or rounded.		(8)
8 (7)	Seeds white or yellow-red, slightly enveloped by swollen funicle		16 Paris forrestii
+	Seeds yellow-brown, 1/2 enveloped by greenish white or rarely orange, spongy aril formed by enlarged funicle		15 Paris axialis
9 (1)	Stamens 4--6 × as many as outer tepals; seeds enveloped by orange aril		1 Paris dunniana
+	Stamens 2 or 3 × as many as outer tepals; seeds enveloped by red aril.		(10)
10 (9)	Leaves with white, yellowish, or purple markings.		(11)
+	Leaves without markings.		(13)
11 (10)	Leaves with purple markings; stamens ca. 3 × as many as leaves		12 Paris polyandra
+	Leaves with white or yellowish markings; stamens 2 × as many as leaves.		(12)
12 (11)	Outer tepals as many as leaves, shorter than inner ones		10 Paris luquanensis
+	Outer tepals fewer than leaves, longer than inner ones		11 Paris marmorata
13 (10)	Plants pubescent or papillose-pubescent.		(14)
+	Plants glabrous or nearly so.		(15)
14 (13)	Free portion of connective 0.5--1 mm		8 Paris mairei
+	Free portion of connective 13--15 mm		9 Paris wenxianensis
15 (13)	Free portion of connective 6--15 mm.		(16)
+	Free portion of connective 1--4(--5) mm (except in P. polyphylla var. pseudothibetica).		(17)
16 (15)	Inner tepals pendulous, margin undulate		7 Paris undulata
+	Inner tepals (if present) not pendulous, margin not undulate		14 Paris thibetica
17 (15)	Filaments ca. 1 mm, shorter than free portion of connective		5 Paris daliensis
+	Filaments more than 2 mm, longer than free portion of connective.		(18)
18 (17)	Free portion of connective transversely ellipsoid, subglobose, or shortly conical, as wide as or wider than long		13 Paris fargesii
+	Free portion of connective inconspicuous or longer than wide.		(19)
19 (18)	Leaves (18--)23--26 × (11--)14--16 cm		3 Paris vietnamensis
+	Leaves 5--17 × 2--11 cm.		(20)
20 (19)	Leaves ovate		2 Paris cronquistii
+	Leaves oblong to lanceolate.		(21)
21 (20)	Inner tepals dark purple, usually much shorter than outer ones		4 Paris delavayi
+	Inner tepals yellow-green, usually slightly shorter or longer than outer ones		6 Paris polyphylla