Description from Flora of China
Arum ternatum Thunberg in Murray, Syst. Veg., ed. 14, 827. 1784; Arisaema loureiroi Blume; A. macrourum (Bunge) Kunth; A. ternatum (Thunberg) Schott; Arum atrorubens Sprengel (1826), not Linnaeus (1753); A. bulbiferum Salisbury; A. bulbosum Persoon ex Kunth; A. fornicatum Roth; A. macrourum Bunge; A. subulatum Desfontaines; A. triphyllum Houttuyn (1774), not Linnaeus (1753); Hemicarpurus fornicatus (Roth) Nees; Pinellia angustata Schott; P. koreana K. H. Tae & J. H. Kim; P. ternata var. angustata (Schott) Engler; P. ternata var. giraldiana Engler; P. ternata var. subpandurata Engler; P. ternata var. vulgaris Engler; P. tuberifera Tenore, nom. illeg. superfl.; Typhonium tuberculigerum Schott.
Tuber globose, 1-2 cm in diam. Leaves 2-5; petiole 15-20 cm, base sheathing; bulbils present in sheath, at proximal or middle part of petiole, and at base of leaf blade; leaf blade 3-foliolate, sometimes pedate with 5 leaflets; leaflets greenish abaxially, green adaxially, oblong-elliptic or lanceolate, base cuneate, apex acuminate; anterior leaflet 3-10 × 1-3 cm; lateral leaflets (3-)4-7.5 × 1.8-2.3 cm, with 7-9(or 10) primary lateral veins per side, forming a collective vein along margin. Inflorescence including peduncle longer than petioles, 25-35 cm; peduncle 15-25 cm. Spathe greenish or whitish green, rarely purplish, slightly constricted, 6-7 cm; tube narrowly cylindric, 1.5-2 cm; limb green and usually violet at margin, oblong, 4-5 × ca. 1.5 cm, apex obtuse or acute. Spadix 9-10 cm; female zone ca. 2 cm, adnate to spathe; female flowers densely arranged; pistil 2.1-2.2 mm; ovary ovoid, ca. 1.8 × 1-1.1 mm; style distinct, attenuate; stigma very small, ca. 0.2 mm in diam., not broader than style; sterile zone between female and male flowers ca. 3 mm; male zone 5-7 mm; thecae elongate, ca. 1.2 mm, opening by a slit; appendix erect or sigmoid, green to violet, 6-7(-8) cm. Berries yellowish green to whitish, ovoid, with persistent stigma and style, 1-seeded. Fl. May-Jul, fr. Jul-Sep. 2n = 28, 54, 72, 104, 115, 116, 128.
Pinellia ternata is a highly variable species in morphology and cytology. It differs from other Pinellia species by having bulbils at different parts of the petiole; bulbils on each petiole may be 1, 2, or 3. Fourteen sheets of specimens in the Herbarium of the Royal Botanic Garden Edinburgh (E), have been studied and counted: six specimens have bulbils at the proximal part of the petiole; five specimens show bulbils at the median part; one specimen has three bulbils located at the proximal and median parts and at the distal part; another specimen has two bulbils at the distal and proximal parts (6 May 1975, N. Togash s.n. from Tokyo); and one has two bulbils found at the distal and the median parts. After examining the variability in position and number of bulbils, we suggest that "Pinellia zinguiensis" H. Li (nom. nud.), with bulbils at both the distal and proximal parts of the petiole, must be a synonym of P. ternata. For the same reason, Engler’s four variants (P. ternata var. angustata, P. ternata var. giraldiana, P. ternata var. subpandurata, and P. ternata var. vulgaris) may not represent any independent systematic taxa. Pinellia koreana was described from Korea as differing by its pedate leaf blades with five leaflets; but strong growing plants sometimes produce pedate leaf blades, and, therefore, this is only a further synonym of P. ternata. It was collected from Korea, Mt. Chiri, 480 m, 10 Jun 1999 (fl.), K.-H. Tae 99-001 (holotype, TUT).
The poisonous tubers are used in traditional Chinese medicine for treating coughs, reducing phlegm, stopping vomiting, and externally for treating mastitis and otitis media. The plant is also used ornamentally.
Grasslands, secondary forests, wastelands, cultivated lands; below 2500 m. Widely distributed in China, excluding Nei Mongol, Qinghai, Xinjiang, and Xizang [Japan (including Ryukyu Islands), Korea; naturalized in Europe and North America].
In his article, Dan Nicolson (Taxon 26: 338. 1977) mentioned the following: ‘Breitenbach's paper on floral organization in Arum ternatum (Bot. Zeit. 37: 687-692. Oct. I879) commented (p. 687): "Recently I had the opportunity, in the local botanical garden [Leipzig], to study Arum ternatum Thnbg. = Pinellia ternata Ten." The latter binomial, appearing for the first time and often accepted as validly published, actually is not accepted by Breitenbach. This is the only time Breitenbach uses the binomial as opposed to Arum ternatum which appears nine times, including in the title, the summary, and the notes for the illustrations. He attributes the combination to Tenore who only published Pinellia tuberifera. In short, Pinellia ternata (Thunb.) Tenore ex Breitenbach was not accepted by Breitenbach and fails under Article 34. Makino (1901) seems to be the first author to validly publish Thunberg's epithet in Pinelllia.”