Dinetus duclouxii

Nomenclature

Accepted name/Authority/Place of publication:

Dinetus duclouxii (Gagnep. & Courchet) Staples, Novon 3: 199. 1993.

Synonyms:

Porana duclouxii Gagnep. & Courchet, Notul. System. (Paris) 3: 153. July 1915. TYPE: China. Yunnan: Ky-y, près My-lè [Mile Xian], 5 Sep. 1907, Ducloux 5459 (lectotype: P).

Ipomoea #26 F.B. Forbes & Hemsl., Index Florae Sinensis 2: 163 1890 [J. Linn. Soc. Bot. 26: 163. 1890], nomen, based on Faber 1199.

Porana triserialis C.K. Schneid. in Sargent, Pl. wilson. 3: 356. 1916. TYPE: China. Sichuan: Tung River valley, nr. Wa-shan, Sep. 1908, A. Henry 3220 (holotype: A; isotypes: A, BM, E, F, K, MO, US).

Porana triserialis var. lasia C.K. Schneid. in Sargent, Pl. wilson. 3: 362. 1916

Porana duclouxii Gagnep. & Courchet var. lasia (C.K. Schneid.) Hand.-Mazz., Symb. sin. 7: 809. 1936. TYPE: China. Yunnan: “probably at Mengtsze” [Mengzi], A. Henry 9229c, pro parte (holotype: A).

Porana lutingensis Lingelsh. in Pax, Repert. Spec. Nov. Regni Veg. 12: 471. 1922. TYPE: China. Sichuan: “Lu ting tschiau [Luding Xian], Talhänge des Tung ho an der Strasse nach Wa sse kou, Ta tsien lu,” A. Limpricht 1628 (holotype: not found; photo and fragment A, ex WRSL).

Porana lobata C.Y. Wu Yunnan Trop. & Subtrop. Floris. Res. Rep. 1: 105. tab. 34, f. 3. 1965. TYPE: China. Sichuan: Kwang-yun Hsien [Guangyuan Xian], 28 Sep. 1930, F.T. Wang 22608 (holotype: KUN; isotypes: NAS, PE).

Description

Habit:

Perennial twiner, branches often pendant, 1–7 m long, often viscid glandulose; roots enlarged, conical, 3–6.8 by 4.2–5.1 cm, yellowish when fresh; finer roots fibrous. Stem twining, terete, faintly striate or smooth, sometimes minutely verruculose, stramineous to reddish-purple, glabrous or ± viscid. Indumentum yellowish to reddish, a mixture of simple trichomes and multicellular, glandular trichomes, with or without a swollen apical cell.

Leaves:

Leaf petiole 2.2–7.0 cm long; blade variable in shape, broadly ovate to cordate, hastate, or sagittate in outline, 6.4–11.5 by 4.3–9.6 cm, base deeply cordate, sagittate, or hastate with broadly rounded lobes, margins entire, undulate, or palmately 3-lobed or cleft, or + irregularly incised, apex attenuate, mucronulate, texture chartaceous, adaxially brownish, glabrous to ± viscid puberulent, abaxially grayish, glabrous to densely viscid tomentose; lower order veins covered with minute pustules or vesicles.

Inflorescences:

Inflorescence 8–17(–40) cm long, sometimes with a small raceme arising from lower axil; lower bracts petiolate, petiole 3–18 mm long, blade ovate, 1.9–4.4 by 1–2.7 cm, base shallowly cordate, apex attenuate, deciduous; upper bracts diminishing in size, becoming sessile, linear-subulate, 4–8 by < 1 mm, deciduous; pedicels filiform, 6–11 mm; bracteoles 3, unequal, immediately subtending calyx, ovate, ca. 1 mm long, to lanceolate, 3–5 by < 1 mm, flat or undulate, in fruit enlarging and becoming reflexed along pedicel, circular, ovate or obovate, unequal, 3–11(–14) by 1–5(–8) mm, apex often inequilateral.

Flowers:

Flowers showy, fragrant; buds slenderly clavate to spatulate, apex acute to obtuse. Sepals unequal, triangular-ovate to lanceolate to linear-subulate, outer 3 larger, 3–8 by 1–2 mm, inner 2 smaller, 1.5–4 by 0.5–1 mm, base truncate, margins entire, flat, undulate, or crinkled distally, apex acute to acuminate, texture herbaceous, smooth to faintly striate, glabrous or viscid pubescent; venation not visible. Corolla salverform to narrowly funnelform, 2.2–3.5 by 1.7–3.4 cm, diaphanous, tube narrow, yellowish inside, limb flaring, white to pale yellow, lavender, blue, reddish, or violet, deeply 5-parted, lobes obtuse to rounded, mucronate. Stamens unequal, 5–10 mm long, usually triseriate, yellowish-white; filaments (3–)5–8 mm long, basal 2 mm villous, otherwise glabrous; anthers linear, 1.5–2 mm, yellowish-white; pollen 3-colpate, oblate spheroidal to obtusely triangular, ca. 10 by 12–14 micrometer, surface psilate. Pistil shorter than calyx, 4(–5) mm long; disc annular, slightly 5-lobed, or absent; ovary ovoid, ca. 1 mm tall; style ca. 2 mm long, white; stigma oblong to narrowly obovoid, ca. 0.5 mm long, emarginate to bilobed, sometimes inequilateral, green when fresh, pale gray when dry.

Pollen:

Pollen 3-colpate, oblate spheroidal to obtusely triangular, ca. 10 by 12–14 micrometer, surface psilate.

Fruits:

Fruiting calyx clasping utricle, sepals unequal, bases encircling utricle, distally flattened and flaring; outer 3 sepals narrowly ovate to elliptic, 1.9–3.7 by 0.7–1.3 cm, inner 2 linear-lanceolate to narrowly elliptic, 1.5–2 by 0.3–0.9 cm, margins entire, sometimes undulate or ciliolate, apex acuminate, acute, obtuse or rounded, apiculate, texture stiffly chartaceous, tan to purple-brown when dried, glabrous or ± viscid. Utricle globose to broadly ellipsoid, 5–8 by 5–7 mm, apiculate by persistent 1–2 mm long style, thinly chartaceous to membranous, sometimes hyaline, smooth to faintly striate, pale yellowish-tan to dark chestnut brown, glabrous.

Seeds:

Seed (sub) globose, 5–6 mm by 4–5 mm, reddish-brown to black-brown, scurfy yellowish at first, later smooth, glabrous.

Author:

G. Staples

References:

Staples, G.W. 2006. Blumea 51: 403–491.

Biogeography, Ecology and Natural History

Distribution Map:

Distribution:

China (Hubei, Sichuan, Yunnan) (Map).

Ecology:

Roadsides, margins
of fields, grassy areas, thickets, stream banks, in scrub, often in rocky or
stony situations and several times collected on calcareous or limestone
substrates at (120–)900–2000(–4000) m elevation.

Phenology:

Months	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Flowering specimens		3			6	3	5	14	16	8	1	1
Fruiting specimens									5	8	3

Author:

G. Staples

References:

Staples, G.W. 2006. Blumea 51: 403–491.

Other information

General comments:

The following unique characters distinguish Dinetus duclouxii: markedly unequal, glabrous or glandular flowering sepals; a salverform corolla with a slender tube; unequal stamens inserted in (2 or) 3 series below the middle of the tube; 3 prominent bracteoles, which become accrescent and reflexed in fruit, and are borne immediately below the calyx. The presence of viscid, multicellular glandular trichomes on the vegetative parts is also unique to this species, though some individuals have so few as to seem glabrous.

Infraspecific Characters:

Dinetus duclouxii is variable in leaf shape, corolla color, relative stamen length, and density of glandular indumentum. This variation has provided the foundation for taxonomic overdescription, with several distinctive phenotypes having received taxonomic recognition. As with numerous other species in the Convolvulaceae, these character states are not taxonomically reliable. The taxonomic concept adopted here recognizes considerable variation as a single polymorphic species.

Corolla color in D. duclouxii varies from white through pale yellow, lavender, pink, reddish, and blue to violet. Of 50 collections citing corolla color, 13 report white or pale yellow and 37 report darker colors. This is very near a 3:1 ratio, which suggests a simple case of incomplete dominance in corolla color. No correlation is apparent between corolla color and geographic distribution or ecological factors. I believe the white flowered plants do not warrant taxonomic recognition.

Authorship for webpage

Editor:

George Staples, Esmond Er

Contributors:

Classification:

Dinetus duclouxii

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