32. POLYGONACEAE Family 32. POLYGONACEAE J.A. NYBERG & A.G. MILLER Herbs or shrubs, sometimes aquatic, rarely climbing. Leaves usually alternate, simple or lobed, sometimes absent. Stipules connate forming an often membranous sheath (the ocrea). Flowers bisexual or unisexual, actinomorphic, in racemes, panicles or clusters. Perianth with 3-6 segments, freeor fused, oftenaccrescent and enclosing the fruit, sometimes winged or toothed or bearing spines. Stamens 6-15. Ovary superior, I-celled with a solitary, basal ovule; styles 2-4. Fruit a trigonous or biconvex nutlet, sometimes winged or beset with bristles, sometimes hidden by the accrescent perianth lobes. Antigonum leptopus Hook. & Arn. is cultivated as an ornamental in Arabia. It is a shrubby climber with cordate leaves, tendrils and white or pink, papery perianth segments surrounding the nutlets. 1. Shrubs; leaves less than 10mm long 2 + Annual or perennial herbs; or if shrubs then leaves more than 20mm long 4 2. Leaves ovate; fruitscovered by the accrescent, inner pair of perianth lobes 8. Atraphaxis + Leaves linear or minute and soon deciduous; Fruit winged or covered with stiffsetae, not covered by the accrescent perianth lobes 3 3. Fruit 3-winged; leaves linear, persistent 9. Pteropyrum + Fruit 4-winged or covered with stiffsetae; leaves minute, soon deciduous 7. Calligonum 127 POLYGONACEAE 4. Perianth segments indurated in fruit and bearing 3 rigid spines 5 + Perianth segments sometimes accrescent but not indurated in fruit, sometimes toothed but not bearing rigid spines 6 5. Leaves simple; flowers in axillary clusters 6. Emex + Leaves sinuously lobed; flowers in elongated spikes 3. Oxygonum 6. Leaves large, all basal, palmately-nerved 4. Rheum + Leaves small or medium-sized; stem leaves usually present, not palmately- nerved 7 7. Inner perianth segments accrescent and winged or toothed in fruit 5. Rumex + Inner perianth segments never accrescent, nor winged or toothed in fruit 8 8. Flowers in axillary clusters sometimes forming lax spikes; ocreae 2-lobed, lacerate 1. Polygonum + Flowers in globose heads or spikes; ocreae cylindric, truncate or fringed with bristles 2. Persicaria 1. POLYGONUM L. Annual or perennial herbs. Ocreae 2-lobed, membranous, lacerate. Leaves narrow, entire. Flowers 1-6 in axillary clusters. Perianth 4-5-lobed. Stamens 4-5, not dilated at the base. Styles 2-3. Nuts trigonous. 1. Bushy, clump-forming perennial; stems up to 1.5m 2. P. palaestinum + Erect, ascending or prostrate annual herbs; stems up to 60cm 2 2. Leaves linear-spathulate, up to 10(-15)mm; nuts c.lmm; stems prostrate 3. P. corrigioloides + Leaves elliptic-lanceolate or narrowly elliptic-oblong, 10-50mm; nuts 2- 3.5mm; stems erect, ascending or prostrate 3 3. Inflorescence becoming leafless and spike-like above; all leaves deciduous at length; pedicels longer than the flowers 1. P. argyrocoleum + Inflorescence leafy; leaves persistent; pedicels shorter than the flowers 4. P. aviculare 1. P. argyrocoleum Steud. ex Kunze in Linnaea 20: 17 (1847). Syn.: P. patulum sensu Collenette (1985) non M. Bieb. Illustr.: Collenette (1985 p.403) as P. patulum. Glabrous annual; stems erect or ascending, up to 60cm. Ocreae brownish at the base. Leaves narrowly elliptic-lanceolate, 10-50 x2-5mm, acute, attenuate below, deciduous at length. Inflorescence of 2-6-flowered clusters, leafy below, becoming leafless and spike-like above; pedicels longer than the flowers. Perianth 2.2-2.5mm; lobes green with pinkish margins. Nuts c.2mm, smooth, shining. Map 135, Fig. 23. Roadsides, waste ground and sometimes a serious weed of cultivation; 10-2300m. 128 2. Persicaria Saudi Arabia, UAE, Qatar, Kuwait. Iraq, Iran, Afghanistan, Armenia and C Asia. P. argyrocoleum is related to and often confused with P. equisetiforme Sibth. & Sm., a perennial species and native of the Mediterranean region. Immature plants of P. argyrocoleum, with leafy inflorescences, can be confused with P. aviculare L. Records of P. patulum M. Bieb. from Kuwait and possibly P. equisetiforme from Qatar are referable to P. argyrocoleum. 2. P. palaestinum Zoh., Fl. Palaest. 1: 341 (1966). Bushy, glabrous, perennial herb; stems erect, up to 1.5m. Ocreae brownish at the base. Leaves narrowly elliptic-lanceolate, 10-30(-60)x2-5(-8)mm, acute, attenuate below, soon deciduous. Inflorescence of2-3-flowered clusters, forming an interrupted spike, leafless above; pedicels shorter than the flowers. Perianth 3^taim; lobes green with white margins. Nuts 2-3mm, smooth, shining. Map 136. Sandy wadi-beds amongst lava flows; 700-800m. Saudi Arabia. Palestine. In Arabia confined to a small area in the north of Saudi Arabia where it is locally common. 3. P. corrigioloides Jaub. & Spach, 111. pi. or. 2: 34 (1845). Glabrous, annual herb; stems prostrate, up to 30cm. Leaves linear-spathulate, 5- 10(-15)x 0.5-1.5mm, obtuse, attenuate below. Inflorescence leafy, of 2-6-flowered clusters; pedicels longer than the flowers. Perianth 1-1.5mm; lobes green with white or pinkish margins. Nuts c.lmm, smooth, shining. Map 137. Muddy areas and pond margins; 1800-2800m. Yemen (N). Iraq, Iran, Pakistan, Afghanistan and C Asia. 4. P. aviculare L., Sp. pi.: 362 (1753). Glabrous, annual herb; stems erect or prostrate, up to 30cm. Leaves narrowly elliptic-oblong, 10-40 x 2-10mm, acute or obtuse, cuneate or attenuate below; stem leaves often larger than those on the branches. Inflorescence leafy, of 1-6-flowered clusters; pedicels shorter than the flowers. Perianth 2-3mm; lobes green with pinkish margins. Nuts 2-3.5mm, smooth, shining. Map 138. Weed ofcultivated ground; 1800-2900m. Saudi Arabia, Yemen (N). Cosmopolitan. 2. PERSICARIA L. Annual or perennial herbs, sometimes aquatic. Ocreae cylindrical, truncate or with a terminal fringe of bristles. Leaves oblong-ovate or lanceolate, entire. Flowers in globose heads or spikes. Perianth 4-5-lobed. Stamens 5-8, dilated at the base. Styles 2-3. Nuts trigonous or biconvex. 129 POLYGONACEAE Wilson, K.L. (1990). Some widespread species of Persicaria and their allies. Kew Bull. 45(4): 621-636. 1. Flowers in globose heads subtended by an involucral leaf 1. P. nepalensis + Flowers in spikes, not subtended by an involucral leaf 2 2. Leaves oblong-ovate; base rounded or cordate 2. P. amphibia + Leaves lanceolate to elliptic-lanceolate; base attenuate, cuneate or rarely rounded 3 3. Ocreae with a terminal fringe offine bristles; leaves not gland-dotted 4 + Ocreae without a terminal fringe of fine bristles, rarely shortly ciliate; leaves minutely gland-dotted 6 4. Spikes slender, interrupted, 'zig-zagging' when immature; leaves narrowly lanceolate 8. P. decipiens + Spikes densely-flowered, never 'zig-zagging'; leaves lanceolate to elliptic- lanceolate 5 5. Ocreae sub-equal or shorter than the terminal bristles; bristles up to 1.5cm 7. P. barbata + Ocreae much longer than the terminal bristles; bristles up to 5mm 6. P. maculosa 6. Nuts not dimpled; inflorescence glabrous or at most with a few scattered glands 3. P. glabra 4- Nuts dimpled on both surfaces; inflorescence glandular 7 7. Erect, robust perennial; petioles l-5cm; perianths 3-5mm; flowers often exceeding the bracts 5. P. senegalensis + Erect or ascending annual; petioles up to 1cm; perianths 1.7-3mm; flowers never exceeding the bracts 4. P. lapathifolia 1. P. nepalensis (Meissner) Gross in Bot. Jahrb. Syst. 49: 277 (1913). Syn.: Polygonum nepalense Meissner, Monogr. Polyg.: 84 (1826). Prostrate annual herb; stems up to 30cm. Ocreae brown, 5-10mm, truncate, not fringed, sparsely brown-pubescent. Leaves ovate or elliptic, up to 5 x 3cm, acute, abruptly narrowed and auriculate at the base, sparsely pubescent; petiole winged. Flowers in globose heads; heads 5-10mm diam., 1-3 from the upper leaf axils, subtended by a sessile involucral leaf; peduncles with stalked glands. Perianth pink or white, c.3mm. Nut biconvex, minutely pitted, c.2mm, dull. Map 139, Fig. 23. Rare weed of cultivation; 2600-3100m. Yemen (N). Tropical Africa and tropical Asia. 2. P. amphibia (L.) S.F. Gray, Nat. Arr. Brit. PI. 2: 268 (1821). Syn.: Polygonum amphibium L., Sp. pi.: 361 (1753). Illustr.: Collenette (1985 p.402). Glabrous, aquatic* perennial; stems rooting at the nodes. Ocreae brown, up to 2cm, truncate. Leaves floating, long-petiolate, oblong-ovate, 7-10(-17)x2-4cm, 130 2. Persicaria Fig. 23. Polygonaceae. A, Persicaria amphibia: Aa, flowering shoot (x 0.6). B, P. nepalensis: Ba, flowering shoot (x 1). C, P. glabra: Ca, flowering shoot (x 0.3); Cb, ocrea (x 2); Cc, nutlet (x 10). D, P. maculosa: Da, ocrea (x 2). E, P. barbata: Ea, ocrea (x 2). F, P. senegalensis: Fa, nutlet (x 10). G, Polygonum argyrocoleum: Ga, habit (x 1). 131 POLYGONACEAE rounded at the tip, rounded or cordate below. Racemes solitary or sometimes paired, densely flowered, 3-4cm. Perianth white or pink, c.3.5mm. Nut biconvex, c.2.5mm, shining. Map 140, Fig. 23. *A terrestrial form also occurs; this has erect stems and lanceolate, subsessile, pubescent leaves. Ponds and pond margins; 300-2650m. Saudi Arabia, Yemen (N). Europe, temperate Asia, N Africa and N America. 3. P. glabra (Willd.) M. Gomez in An. Inst. Segunda Ensenanza Habana 2:278 (1896). Syn.: Polygonum glabrum Willd., Sp. pi. 2 (1): 447 (1799). Robust, glabrous, perennial herb; stems erect, up to lm. Ocreae reddish brown, up to 3cm, truncate, not fringed. Leaves lanceolate, up to 25 x 5cm, acuminate, cuneate below, minutely yellow-glandular. Racemes 2-4 at the ends of branches, densely flowered, 5-10cm; peduncles and racemes glabrous or very sparsely glandular. Peri anth pink, c.3.5mm. Nut biconvex or trigonous without dimpled faces, c.2.5mm, shining. Map 141, Fig. 23. Margins of ponds and streams; 100-2300m. Saudi Arabia, Yemen (N & S), Socotra, Oman. Tropics of Africa, Asia and America. 4. P. lapathifolia (L.) S.F. Gray, Nat. Arr. Brit. PL 2: 270 (1821). Syn.: Polygonum lapathifolium L., Sp.