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FOC | Family List | FOC Vol. 16 | Convolvulaceae

15. Ipomoea Linnaeus, Sp. Pl. 1: 159. 1753.

番薯属 fan shu shu

Calonyction Choisy; Exogonium Choisy; Mina Llave & Lexarza; Pharbitis Choisy; Quamoclit Miller.

Herbs or shrubs, often twining, sometimes prostrate, erect, or floating. Leaves petiolate, entire, lobed, or divided. Inflorescences mostly axillary, cymose, 1- to many flowered, rarely paniculate; bracts various. Flowers small to large. Sepals persistent, equal to unequal, ± enlarged in fruit. Corolla variously colored, rarely yellow, funnelform, campanulate, or salverform; limb 5-lobed to entire, midpetaline bands well defined. Stamens included or exserted; filaments filiform, usually unequal, dilated and pubescent basally; anthers ovate or linear, longitudinally dehiscent, not twisted; pollen globular, pantoporate, finely spiny. Disc ringlike. Ovary 2-4-loculed, 4- or 6-ovuled. Style 1, filiform, included or exserted; stigma capitate, or 2- or 3-globulose. Capsule globose or ovoid, 4- or 6-valved. Seeds 4(-6) or fewer, glabrous or pubescent.

Approximately 500 species: widely distributed in tropical to warm temperate regions, especially of North and South America; 29 species in China.

The following are cultivated in China and may escape from gardens in the south: Ipomoea quamoclit Linnaeus (= Quamoclit pennata (Desrousseaux) Bojer), I. hederifolia Linnaeus (widely misidentified as Quamoclit coccinea (Linnaeus) Moench or I. coccinea Linnaeus), I. Sloteri (House) van Ooststroom ( = Quamoclit sloteri House), and I. tricolor Cavanilles. These have been included in the key to species and given no further treatment. Ipomoea fulvicoma Hance was originally described from Hong Kong, but no material of the species was available for study. Ipomoea lancunosa Linnaeus was reported from Zhejiang by Chiu et al. (Acta Bot. Yunnan. 16: 231-234. 1994), but its occurrence has not been verified by us, and the species has not been included here.

The generic concept for Ipomoea in this flora differs from that followed in the Fl. Reipubl. Popularis Sin. in that Pharbitis, Calonyction, Quamoclit, and Mina are recognized as infrageneric taxa, following D. F. Austin (Taxon 28: 359-361. 1979; emended, 29: 501-502. 1980) and most other twentieth century floras. In any case, cultivated species including those referable to Quamoclit and Mina that were treated in the Fl. Reipubl. Popularis Sin. account are mostly omitted in the Flora of China.

1 Sepals distinctly awned at or below apex; corolla salverform with a long narrow tube; stamens and pistil mostly exserted.   (2)
+ Sepals rounded to acuminate, emarginate, or mucronulate but never awned at or near apex; corolla mostly funnelform, or campanulate, sometimes salverform; stamens and pistil mostly included, sometimes exserted.   (6)
2 (1) Corolla longer than 4.5 cm, white or purplish; outer sepals 5-12 mm (excluding awn), inner sepals 7-15 mm (excluding awn).   (3)
+ Corolla 3-4.5 cm, scarlet, rarely pure white; outer sepals 2-4.5 mm (excluding awn), inner sepals 3-6 mm (excluding awn).   (4)
3 (2) Corolla white, tube slightly widened apically or not, 7-12 cm; stamens and style exserted   21 Ipomoea alba
+ Corolla purplish, tube distinctly widened apically, 3-6 cm; stamens and style scarcely exserted or not   22 Ipomoea turbinata
4 (4) Leaves cordate, entire, angled, or palmately lobed, not pinnately parted I.hederifolia   (4)
+ Leaves linear-lanceolate, linear, or filiform, pinnately parted.   (5)
5 (5) Leaf segments ca. 3-7 on either side of midvein, linear or linear-lanceolate I.sloteri   (5)
+ Leaf segments more numerous, linear or filiform I. quamoclit   (1)
6 (1) Corolla ca. 10 cm or longer, salverform with a long and narrow tube, white or with greenish midpetaline bands; seeds long pubescent at least on margin; plants large twiners.   (7)
+ Corolla usually less than 10 cm, funnelform or campanulate, rarely salverform and then not longer than ca. 7 cm; seeds pubescent or glabrous; plants large to small twiners, or prostrate or erect.   (8)
7 (6) Stamens inserted near mouth of corolla tube; sepals subequal or outer sepals slightly longer than inner sepals   29 Ipomoea aculeata var. mollissima
+ Stamens inserted near base of corolla tube; sepals equal or outer 2 shorter than inner ones   28 Ipomoea violacea
8 (6) Sepals hairy abaxially or with fimbriate or ciliate margin.   (9)
+ Sepals glabrous, sometimes muricate or dentate on veins.   (23)
9 (8) Peduncles very short ( < 1.5 cm) or absent; corolla to 1.9 cm.   (10)
+ Peduncles mostly longer, well developed; corolla mostly longer than 2 cm.   (12)
10 (9) Herbs erect to decumbent; leaf blade cuneate and attenuate basally   4 Ipomoea polymorpha
+ Herbs twining or prostrate; leaf blade cordate basally.   (11)
11 (10) Ovary and capsule pubescent; pedicel absent or very short, to 3 mm; outer sepals linear-acuminate from an ovate base; corolla pink or purplish, 7-9 mm   1 Ipomoea eriocarpa
+ Ovary and capsule glabrous; pedicel 8-15 mm; outer 3 sepals deltate-lanceolate, base auriculate; corolla white, 12-19 mm   2 Ipomoea biflora
12 (9) Flowers clustered at peduncle apex (capitate), subtended by 1 or more involucrate bracts.   (13)
+ Flowers clustered at apex of peduncle or not, not distinctly involucrate.   (14)
13 (12) Leaves palmately divided nearly to base; bracts oblong; outer sepals lanceolate, apex acute; corolla funnelform, white   9 Ipomoea pes-tigridis
+ Leaves entire; bracts navicular; outer sepals elliptic-spatulate, apex obtuse; corolla salverform, pink or purple   10 Ipomoea pileata
14 (12) Sepals 4-5 mm or less   14 Ipomoea obscura
+ Sepals ca. 5 mm or longer.   (15)
15 (14) Erect shrubs or scandent subshrubs; sepals elliptic or ovate to circular, apex rounded, obtuse, or emarginate.   (16)
+ Twiners or prostrate; sepals narrower, apex usually acute or acuminate, rarely obtuse.   (17)
16 (15) Sepals 13-15 mm, apex obtuse or emarginate; corolla 5.5-6.5 cm; scandent subshrubs; leaves ovate-cordate, lateral veins ca. 14 pairs   26 Ipomoea soluta var. alba
+ Sepals 5-6 mm, apex rounded; corolla 7-9 cm; erect shrubs; leaves ovate or ovate-oblong, lateral veins 7-9 pairs   27 Ipomoea carnea subsp. fistulosa
17 (15) Sepals long attenuate, or long and linear-acuminate apically, herbaceous; corolla bluish aging to pinkish.   (18)
+ Sepals acute, acuminate, or obtuse apically, mucronulate or not, not long attenuate, herbaceous, membranous, or leathery; corolla reddish, purplish, lilac to pink, or white.   (19)
18 (17) Outer sepals lanceolate basally, with a long linear acumen, spreading hirsute basally   7 Ipomoea nil
+ Outer sepals lanceolate to broadly lanceolate basally, long and gradually attenuate apically, appressed hairy   8 Ipomoea indica
19 (17) Outer sepals 5-10 mm, mucronulate, glabrous to pilose abaxially, margin ciliate or fimbriate; corolla 1.5-4 cm.   (20)
+ Outer sepals 10-16 mm, not mucronulate, purplish bristly or hirsute abaxially, margin neither ciliate nor fimbriate; corolla 5-7 cm.   (21)
20 (19) Plants with subterranean tubers; stems mostly prostrate, rarely twining, rooting at nodes, thick   11 Ipomoea batatas
+ Plants without tubers; stems mostly twining, thinner   12 Ipomoea triloba
21 (19) Plants ± purplish or blackish bristly on stems, petioles, inflorescences, and abaxial side of sepals; leaves deeply 3-7-lobed, lobe margin undulate-serrate   23 Ipomoea setosa
+ Plants ± hirsute; leaves entire or shallowly 3-lobed, lobe margin entire.   (22)
22 (21) Plants densely yellowish hirsute; stamens less than 6 mm, filaments glabrous basally; ovary 2-loculed; stigma 2-lobed   5 Ipomoea hirtifolia
+ Plants short pubescent mixed with longer retrorse hirsute hairs; stamens unequal, longest stamens reaching middle of corolla tube, filaments pubescent basally; ovary 3-loculed; stigma 3-lobed   6 Ipomoea purpurea
23 (8) Outer sepals with 3 dentate keels   3 Ipomoea fimbriosepala
+ Outer sepals not keeled or dentate.   (24)
24 (23) Sepals ca. 1.4 cm or longer.   (25)
+ Sepals less than 1.4 cm.   (26)
25 (24) Sepals subequal, gradually linear-acuminate apically   8 Ipomoea indica
+ Sepals unequal, outer sepals rounded-obtuse apically, inner sepals acute apically   20 Ipomoea wangii
26 (24) Leaves palmately lobed to palmately compound.   (27)
+ Leaves not palmately divided.   (31)
27 (26) Leaves palmately parted to base; pseudostipules (small leaves of axillary shoot) often present   19 Ipomoea cairica
+ Leaves palmately lobed to or mostly below middle, but not to base; pseudo-stipules absent.   (28)
28 (27) Stems twining; sepals rounded or obtuse apically, not mucronulate.   (29)
+ Stems prostrate, rooting at nodes; inner sepals oblong to elliptic-oblong, distinctly mucronulate.   (30)
29 (28) Sepals ± equal or outer 2 shorter, ± circular, broadly elliptic, occasionally oblong, concave; corolla funnelform   24 Ipomoea mauritiana
+ Sepals unequal, outer 2 longer, ovate to oblong, ± flat; corolla ± salverform   23 Ipomoea setosa
30 (28) Leaves herbaceous, thin, middle lobe acute or subacute; corolla pink, purple, or white; subterranean tubers present; plants cultivated, occasionally escaping   11 Ipomoea batatas
+ Leaves fleshy, middle lobe obtuse or emarginate; corolla white with a pale yellow tube and a dark red center; without subterranean tubers; plants of sandy seashores   18 Ipomoea imperati
31 (26) Plants large, woody, glabrous twiners; flowers in axillary panicles, fundamental units cymose   25 Ipomoea sumatrana
+ Plants smaller, mostly herbaceous twiners, or prostrate plants, glabrous or pubescent; flowers in few- to several-flowered axillary cymes, or solitary in leaf axils.   (32)
32 (31) Corolla ± salverform   16 Ipomoea marginata
+ Corolla funnelform to campanulate.   (33)
33 (32) Corolla to 2.5 cm   14 Ipomoea obscura
+ Corolla ca. 3 cm or longer.   (34)
34 (33) Plants of marshy places or aquatic, often cultivated for food (stems and leaves eaten); stems usually repent and rooting, or floating, thick, fistulose   15 Ipomoea aquatica
+ Plants terrestrial; stems twining or repent.   (35)
35 (34) Stems mostly (or at least partly) twining.   (36)
+ Stems prostrate or trailing, mostly rooting at nodes, rarely twining, usually thick.   (37)
36 (35) Sepals distinctly mucronulate, outer concave; corolla pink or pink-purple, with a darker center   13 Ipomoea littoralis
+ Sepals without a mucro, outer flat; corolla blue, with a paler or white center I. tricolor   (35)
37 (35) Leaves herbaceous, attenuate toward acute or obtuse apex; plants with subterranean tubers, cultivated for edible tubers   11 Ipomoea batatas
+ Leaves ± leathery or fleshy, apex mostly obtuse to broadly rounded, or emarginate; plants without subterranean tubers.   (38)
38 (37) Corolla white or yellowish, with a dark red center; leaves linear, lanceolate, oblong, or ovate (often on the same plant), apex obtuse or emarginate   18 Ipomoea imperati
+ Corolla purple or reddish purple; leaves ± reniform, circular, elliptic, ovate or quadrangular to oblong, apex deeply 2-lobed or emarginate   17 Ipomoea pes-caprae

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