398 POLYGONACEAE. [ Polygonum. 
1. POLYGONUM Linn. 
Herbs, rarely shrubby at the base. Leaves alternate; stipules mem- 
branous, 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 albu- 
minous ; embryo excentric or lateral ; radicle long, superior. 
A large and almost cosmopolitan genus, including over 175 species. The three 
found in New Zealand are all widely distributed. ‘ 
* Stems prostrate. Flowers in axillary clusters. 
Stems long, wiry, sparingly branched. Perianth }in. long. Nut 
minutely striate or punctate x 7 es : 
Stems short, compactly branched. Perianth 4 in. long. Nut smooth 
and polished ~ . 
l. P. aviculare. 
2. P. plebevum. 
** 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 naturalized 
plants appended to this work. 
1. P. avieulare Linn. Sp. Plant. (1753) 362.—A glabrous rigid and wiry 
prostrate annual, much branched from the base; branches 4-2 ft. long, 
straggling, grooved, leafy throughout. Leaves scattered, sessile or shortly 
petioled, 4-1 in. long or more, linear-oblong to lanceolate or linear-lanceo- 
late, rather 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, 
qo-4 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 (1853) 210; Handb. 
N.Z. Fl. (1864) 235; Benth. Fl. Austral. v (1870) 267 ; Cheesem. Man. N.Z. 
Fl. (1906) 589. 
NorTH AND SoutH Istanps: 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 natura- 
lized 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. Inst. 
2. P. plebeium F&. Br. Prodr. (1810) 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, }-1 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, 7y-7’5 in. long, solitary or in clusters of 2-5 in the axils of 
most of the Jeaves; pedicels short. Nnt smaller than in P. aviculare, 
fyae BQ. Vict. pr 3a ee e. eraricrotcaen fBr 
