Herbs, rarely shrubby at the base. Leaves alternate; stipules membranous, usually tubular and closely sheathing the stem. Flowers small, hermaphrodite, clustered; clusters either axillary or in racemes or spikes or panicles; bracts and bracteoles membranous, ochreate; pedicels usually jointed. Perianth 5-partite, green or coloured; segments equal or the 2 or 3 outer ones the largest. Stamens 5–8. Ovary compressed or 3-gonous; styles 2 or 3, free or connate at the base; stigmas usually capitellate. Nuts compressed or 3-gonous, included in the persistent perianth. Seed albuminous; embryo excentric or lateral; radicle long, superior.
A large and almost cosmopolitan genus, including over 150 species. The three found in New Zealand are all widely distributed.
* Stems prostrate. Flowers in axillary clusters.
Stems long, wiry, sparingly branched. Perianth ⅛ in. long. Nut minutely striate or punctate |
1.
P. aviculare. |
Stems short, compactly branched. Perianth 1/12 in. long. Nut smooth and polished |
2.
P. plebeium. |
** Stems erect or ascending above. Flowers in slender terminal spikes.
Leaves 2–5 in., lanceolate. Stipules ciliate and pilose. Spikes very slender, 1–2 in. long |
3.
P. serrulatum. |
For references to several introduced species of
Polygonum, see the list of naturalised plants appended to this work.
1. |
P. aviculare,
Linn. Sp. Plant. 362.—A glabrous rigid and wiry prostrate annual, much branched from the base; branches ½–2 ft. long, straggling, grooved, leafy throughout. Leaves scattered, sessile or shortly petioled, ⅓–1 in. long or more, linear-oblong to lanceolate or linear-lanceolate, rarely broader and elliptic-oblong, acute or obtuse, veins indistinct beneath, margins flat or recurved; stipules brown or reddish near the base, silvery-white above, scarious, lacerate to below the middle. Flowers small, 1/10–⅛ in. long, solitary or in clusters of 2–4 in the axils of nearly all the leaves, very shortly pedicelled. Perianth-segments oblong, obtuse, with a green centre and broad white margins. Nut ovoid, obtusely 3-gonous, very minutely striate or punctate.—
Hook. f. Fl. Nov. Zel. i. 210;
Handb. N.Z. Fl. 235;
Benth. Fl. Austral. v. 267.
NoRth and South Islands: Roadsides and waste places from the North Cape to Foveaux Strait. Most probably an immigrant. Sea-level to 2500 ft.
Knot-grass; Makakaka. November–March.
It is highly doubtful if this is indigenous anywhere outside Europe and northern Asia, although its present distribution is almost cosmopolitan. So far as its occurrence in New Zealand is concerned, I should certainly have relegated it to the list of naturalised plants had it not been for the positive opinion expressed in favour of its nativity by the late Mr. Kirk. Those interested in the subject should read the papers by Kirk and Travers printed in Vols. iv. and v. of the Trans. N.Z. Institute.
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2. |
P. plebeium,
R. Br. Prodr. 420.—Habit of
P. aviculare, but smaller and more compactly branched. Stems prostrate, glabrous or minutely scaberulous, 4–12 in. long, rarely more; branches slender, grooved. Leaves more closely placed than in
P. aviculare, ⅙-½ in. long, linear to linear-oblong, rarely linear-spathulate, obtuse or subacute, midrib evident, margins flat or recurved; stipules short, hyaline, lacerate to the middle. Flowers small, 1/12–1/10 in. long, solitary or in clusters of 2–5 in the axils of most of the leaves; pedicels short. Nut smaller than in
P. aviculare, rhomboid, obtusely 3-gonous, smooth and shining.—
Benth. Fl. Austral. v. 267. P. Dryandri,
Spreng. Syst. ii. 255;
Hook. f. Fl. Nov. Zel. i. 210. P. aviculare
var. Dryandri,
Hook. f. Handb. N.Z. Fl. 236.
North and South Islands: From the Great Barrier Island and the Bast Cape southwards to the Bluff, but local in the North Island, most abundant in Canterbury and Otago. Sea-level to 3000 ft. November–March.
Very closely allied to
P. aviculare, but apparently sufficiently distinct in the smaller size and more compact habit, smaller flowers, and smaller shining and polished nut. A common plant in Australia, tropical Asia, and some parts of Africa.
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3. |
P. serrulatum,
Lag. Gen. et Sp. Nov. 14.—Stems slender, herbaceous, sparingly branched, prostrate and rooting below, ascending or erect above, glabrous, 9–24 in. long or more. Leaves shortly petiolate, 2–5 in. long, lanceolate or linear - lanceolate,
acuminate, narrowed to a rounded or subcordate base, membranous, glabrous or strigose on the midrib beneath, margins serrulate; stipules long, closely sheathing, ciliate and pilose with long erect hairs. Spikes terminal, very slender, simple or sparingly branched, 1–2 in. long; bracts narrow-turbinate, truncate, margins ciliate. Flowers 2–3 to each bract, small, reddish, 1/12 in. long. Perianth-segments oblong, obtuse, glabrous and eglandular. Stamens 5 or 6. Style-branches 2, rarely 3. Nut plano-convex with obtuse margins, rarely trigonous, smooth and shining.—P. minus
var. decipiens,
Hook. f. Handb. N.Z. Fl. 235. P. prostratum,
A. Rich. Fl-. Nov. Zel. Ill (not of B. Br.); A. Cunn. Precur. n. 358;
Raoul, Ghoix, 42;
Hook. f. Fl. Nov. Zel. i. 209.
North and South Islands, Chatham Islands: Abundant along the sides of rivers or in lowland swamps from the North Cape to Canterbury.
Tutu-nawai. November–March.
A widely distributed plant, ranging through south Europe, western Asia, Africa, and Australia. It differs from
P. minus in the larger size, the more slender and much more erect habit, and in the longer and more ciliate stipules.
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