FABACEAE Tribe ABREAE [Draft]

相思子族  xiang si zi zu

Bao Bojian[1]; Michael G. Gilbert[2]

Lianas. Leaves paripinnate; with a short point at the apex of rachis; stipules linear-lanceolate; leaflets many paired, entire. Racemes axillary or leaf-opposed; bracts and bracteoles small. Flowers small, fascicled at nodes; calyx campanulate, subtruncate or with short teeth. Corolla obviously larger than calyx, pink, purple or purple-red; standard ovate, shortly clawed, somewhat fused with staminal tube at base; wings narrow; keels broad. Stamens 9, united in an adaxially split sheath; anthers uniform. Ovary subsessile; style short; stigma capitate, glabrous. Pod oblong, flat, dehiscent; seeds 2 to many, elliptic or spherical, glossy, dark brown or red and black.

One genus and 17 species: 16 in Africa, Madagascar, and Asia, one pantropical; two species in China.

24. ABRUS Adanson, Fam. Pl. 2: 327. 1763.

相思子属  xiang si zi shu

Morphological characters are the same as those of the family.

About 17 species: five in Madagascar, seven in Africa, one in Africa and Asia, one in the Middle East, two in tropical Asia, and one pantropical; two species in China.

Apart from Abrus precatorius, the species are not well defined and one author (Breteler, Blumea 10: 607–624. 1960) suggested a considerable reduction in the number of species recognised. See however Verdcourt (Kew Bull. 24: 235–252. 1970) who is followed here.

1a.       Seeds conspicuously glossy black and red, subglobose; pod 2–3.5 cm, apex emarginate below style       1. A. precatorius

1b.       Seeds uniformly dark brown to almost black, compressed; pod (3–)5–6.5 cm, apex slightly acuminate    2. A. pulchellus

1. Abrus precatorius Linnaeus, Syst. Nat., ed. 12, 2: 472. 1767.

相思子  xiang si zi

Glycine abrus Linnaeus, Sp. Pl. 2: 753. 1753.

Lianas; stem slender, much branched, sparsely white strigose. Leaves paripinnate; leaflets 8–13 paired, membranous, opposite, suboblong, 1–2 Χ 0.4–0.8 cm, truncate and with mucro at apex, rotund at the base, glabrous adaxial, sparsely white strigose abaxial; petiolule short. Racemes axillary, 3–8 cm. Flowers small, dense; calyx campanulate, 4 lobed toothed, white strigose. Corolla purple; flag with triangular claw; wings and keels narrower. Stamens 9. Ovary hairy. Pods oblong, leathery, 2–3.5 Χ 0.5–1.5 cm, dehiscent, with 2–6 seeds. Seeds elliptic, lustrous, red at upper part, black at lower part. Fl. Mar–Jun, fr. Sep–Oct.

Hill forests. Guangdong, Guangxi, Taiwan, Yunnan [widespread in tropics].

The hard and very colorful seeds are often used in necklaces. They are dangerously toxic if ingested when the seed coat is not intact, eg if drilled for a necklace.

2. Abrus pulchellus Wallich ex Thwaites, Enum. Pl. Zeyl. 91. 1859.

美丽相思子  mei li xiang si zi

Climbing lianas. stem slender, sparsely yellow strigose. Leaves paripinnate, alternate; leaflets 6–10 paired, membranous, opposite, suboblong, 0.7–3 Χ 0.4–1 cm, truncate and with mucro at apex, rotund at the base, glabrous adaxial, sparsely white strigose abaxial; petiolule short. Racemes axillary, 3–10 cm. Flowers small, dense, 6–8 mm; calyx campanulate, 4 lobed toothed, white strigose. Corolla pink or purple. Stamens 9. Pods oblong, densely white hairy, 5–6.5 Χ 0.8–1.5 cm, dehiscent, with 6–12 seeds. Seeds elliptic, black-brown, lustrous.

Valley forests; 400–3000 m. Guangxi, Yunnan [Bangladesh, Bhutan,Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Sri Lanka, Thailand, Vietnam; Papua New Guinea].

1a. Indumentum usually at least partly ferruginous, mostly erect, but often gray on leaves or if indumentum gray then leaflets ca. 3 cm and pod 3.5–4.9 cm
.......................................................................................................................  2b. subsp. mollis

1b. Indumentum sparse and grayish, not ferruginous, adpressed (rarely petioles appear to be brown but hairs always pale.

2a..... Leaflets 2–4 cm, base rounded; pod 3.2–9 cm ..................................  2a. subsp. pulchellus

2b.... Leaflets mostly ca. 1 cm, base distinctly subcordate; pod 2–3.3 cm
.....................................................................................................  2c. subsp. cantoniensis

2a. Abrus pulchellus subsp. pulchellus.

美丽相思子(原亚种)  mei li xiang si zi (yuan ya zhong)

Climbing lianas. stem slender, sparsely yellow strigose. Leaves paripinnate, alternate; leaflets 6–10 paired, membranous, opposite, suboblong, 0.7–3 Χ 0.4–1 cm, truncate and with mucro at apex, rotund at the base, glabrous adaxial, sparsely white strigose abaxial; petiolule short. Racemes axillary, 3–10 cm. Flowers small, dense, 6–8 mm; calyx campanulate, 4 lobed toothed, white strigose. Corolla pink or purple. Stamens 9. Pods oblong, densely white hairy, 5–6.5 Χ 0.8–1.5 cm, dehiscent, with 6–12 seeds. Seeds elliptic, black-brown, lustrous.

Valley forests; 400–3000 m. Guangxi, Yunnan [Bangladesh, Bhutan,Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Sri Lanka, Thailand, Vietnam; Papua New Guinea].

2b. Abrus pulchellus subsp. mollis (Hance) Verdcourt, Kew Bull. 24: 248. 1970.

毛相思子  mao xiang si zi

Abrus mollis Hance, J. Bot. 9: 130. 1871

Lianas. stem sparsely yellow villous. Leaves paripinnate; stipule subulate; leaflets 6–10 paired, membranous, oblong, 1–2.5 Χ 0.5–1 cm, truncate and with mucro at apex, rotund at the base, pilose adaxial, densely white villous abaxial. Racemes axillary; rachis 2–4 cm, yellow villous. Flowers 3–9 mm, 4–6 fascicled at nodes; calyx campanulate, densely gray villous. Corolla pink or light purple. Stamens 9. Pods oblong, flat, 3–5(–6) Χ 0.8–1 cm, densely white villous, beaked at apex, with 4–9 seeds. Seeds ovoid, flat, black or dark-brown, slightly lustrous. Fl. Aug, fr. Sep.

* Forests at roadsides or in valleys; 200–1700 m. Fujian, Guangdong, Guangxi, Hainan [Cambodia, Indonesia, Laos, Malaysia, Thailand, Vietnam].

2c. Abrus pulchellus subsp. cantoniensis (Hance)Verdcourt, Kew Bull. 24: 248. 1970.

广州相思子  guang zhou xiang si zi

Abrus cantoniensis Hance, J. Bot. 6: 112. 1868.

Climbing lianas, 1–2 m high; branches slender, smooth, white hairy, caducous when old. Leaves paripinnate, alternate; leaflets 6–11 paired, membranous, oblong or obovate-oblong, 0.5–1.5 Χ 0.3–0.5 cm, truncate or slightly retuse, with mucro at apex, pilose adaxial, strigose abaxial, petiolule short. Racemes axillary. Flowers small, ca. 6 mm, fascicled at shortly rachis; pedicel short. Corolla purple-red or light purple. Stamens 9. Pods oblong, flat, ca. 3 Χ 1.3 cm, beaked at apex, sparsely white strigose, with 4–5 seeds. Seeds black-brown. Fl. Aug.

Forests, hill slopes; ca. 200 m. Guangdong, Guangxi, Hunan [Thailand, Vietnam].



[1] Herbarium, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, People’s Republic of China.

[2] Missouri Botanical Garden c/o Herbarium, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, United Kingdom.