1	"Bracts > 1 mm below calyx, not hiding it, <= 5 mm wide or variously toothed or lobed like leaves"	2
1	"Bracts < 1 mm below calyx, +- hiding it, often > 4 mm wide, not lobed like leaves"	9
2	"Plant glabrous"	3
2	"Plant puberulent to tomentose at least around leaf sinus or at peduncle tip"	6
3	"Bracts elliptic to widely elliptic-oblong, entire"	"Calystegia peirsonii"
3	"Bracts generally linear, entire or lobes basal"	4
4	"Stem +- stiffly erect, intertwined; leaf linear to narrowly triangular, lobes 0 or +- linear, sinus rounded"	"Calystegia longipes"
4	"Stem trailing to strongly climbing, +- not intertwined; leaf triangular to reniform, lobes wider than linear, 2(3)-tipped, sinus V-shaped or +- closed"	5
5	"Stem strongly climbing, > 1 m; leaf triangular, tip acute, sinus V-shaped, bracts rarely lobed"	"Calystegia purpurata subsp. purpurata"
5	"Stem trailing to weakly climbing, generally < 1 m; leaf ovate-triangular to reniform, tip generally rounded to notched, sinus generally +- closed; bracts generally with small lobes"	"Calystegia purpurata subsp. saxicola"
6	"Bracts entire, not lobed like leaves, +- sessile"	"Calystegia occidentalis subsp. occidentalis"
6	"Bracts toothed or lobed like leaves, stalked"	7
7	"Leaf lobes 7--9, linear, finger-like"	"Calystegia stebbinsii"
7	"Leaf +- entire or lobes 2, not linear, not finger-like"	8
8	"Leaf blade widely triangular to +- reniform, tip acute to acuminate or notched, lobes generally 2-tipped; hairs +- densely spreading"	"Calystegia malacophylla subsp. malacophylla"
8	"Leaf blade generally narrowly triangular, tip +- acute, lobes generally 1-tipped; hairs minute or fine"	"Calystegia occidentalis subsp. fulcrata"
9	"Bracts < 4 mm wide"	10
9	"Bracts > 4 mm wide"	13
10	"Plant hairs dense, not appressed"	"Calystegia collina subsp. tridactylosa"
10	"Plant hairs 0 or minutely appressed"	11
11	"Leaf blade narrowly triangular, lobes clearly defined, directed +- basally, base with deep sinus"	"Calystegia peirsonii"
11	"Leaf blade generally triangular-hastate to reniform, lobes not clearly defined, directed +- laterally, base truncate to wedge-shaped or widely rounded, occasionally with shallow sinus"	12
12	"Bracts +- obtuse; plant glabrous"	"Calystegia atriplicifolia subsp. buttensis"
12	"Bracts acute; plant hairs generally minutely appressed"	"Calystegia subacaulis subsp. episcopalis"
13	"Stem trailing or weakly to strongly climbing, >= 1 m"	14
13	"Stem not or only weakly climbing, < 1 m"	22
14	"Plant from rhizomes, stem not woody; peduncle 1-flowered; marshes, riverbanks, or disturbed areas"	15
14	"Plant from woody caudex, lower stem often woody; peduncle often > 1-flowered; generally dry places"	17
15	"Bracts strongly sac-like at base, margins overlapped; corolla generally 55--75 mm"	"Calystegia silvatica subsp. disjuncta"
15	"Bracts not strongly sac-like at base, margins not overlapped; corolla 30--58 mm"	16
16	"Bracts < sepals; corolla generally +- 40 mm"	"Calystegia sepium subsp. binghamiae"
16	"Bracts generally > sepals; corolla 30--58 mm"	"Calystegia sepium subsp. limnophila"
17	"Bracts 16--30 mm wide, strongly keeled to +- sac-like at base"	18
17	"Bracts 4--16 mm wide, flat or +- keeled"	19
18	"Bracts 19--37 mm; calyx 16--25 mm; corolla 47--68 mm; stamens 23--35 mm; s ChI"	"Calystegia macrostegia subsp. amplissima"
18	"Bracts 13--26 mm; calyx 10--22 mm; corolla 36--60 mm; stamens 17--26 mm; n ChI"	"Calystegia macrostegia subsp. macrostegia"
19	"Bracts obtuse"	"Calystegia macrostegia subsp. cyclostegia"
19	"Bracts acute"	20
20	"Leaves hairy"	"Calystegia macrostegia subsp. arida"
20	"Leaves glabrous to puberulent"	21
21	"Leaf blade triangular, > 7 mm wide except basal lobes"	"Calystegia macrostegia subsp. intermedia"
21	"Leaf blade linear to narrowly triangular, < 7 mm wide except basal lobes"	"Calystegia macrostegia subsp. tenuifolia"
22	"Plant hairs 0 or sparsely appressed-minute and leaf triangular-hastate to reniform"	23
22	"Plant tomentose or hairs densely spreading, or leaf not triangular-hastate to reniform"	25
23	"Corolla deep pink or +- purple; leaf reniform, glabrous, +- fleshy; ocean beaches, dunes"	"Calystegia soldanella"
23	"Corolla white or +- yellow (pink- or purple-tinged); leaf +- reniform or not, glabrous or not, not fleshy; inland"	24
24	"Bracts obtuse; plant generally glabrous"	"Calystegia atriplicifolia subsp. buttensis"
24	"Bracts acute; plant generally minutely appressed-hairy"	"Calystegia subacaulis subsp. episcopalis"
25	"Stem well developed, < 100 cm, without basal rosette of leaves"	26
25	"Stem poorly developed, < 30 cm, <= basal rosette of leaves"	28
26	"Plant tomentose; leaf margin wavy"	"Calystegia collina subsp. venusta"
26	"Plant tomentose or hairs densely spreading; leaf margin not wavy"	27
27	"Leaf widely triangular to +- reniform, tip generally obtuse to notched, lobes generally 2-tipped; hairs brown or golden-brown (+- gray); CaR, SN"	"Calystegia malacophylla subsp. malacophylla"
27	"Leaf +- narrowly triangular, tip generally acute, lobes generally 1-tipped (2nd tip 0 or poorly developed); hairs +- gray (+- brown); SnFrB, SCoR, WTR"	"Calystegia malacophylla subsp. pedicellata"
28	"Plant hairs sparse to +- dense, short, spreading to reflexed; leaf margin not or +- wavy"	"Calystegia subacaulis subsp. subacaulis"
28	"Plant +- tomentose; leaf margin wavy"	29
29	"Sepals tomentose"	"Calystegia collina subsp. venusta"
29	"Sepals glabrous or strigose at center"	30
30	"Leaf tip obtuse, lobes generally indistinct, blade triangular to reniform"	"Calystegia collina subsp. collina"
30	"Leaf tip acute, lobes distinct, blade triangular"	"Calystegia collina subsp. oxyphylla"