RUMEX 
135 
(a) R. hydrolapathum var. vulgaris nobis; R. hydrolapathum Trimen in Journ. Bot. xii, 35 (1874) excl. 
var. latifolius . 
leones: — Smith Eng. Bot. t. 2104, as R. aquations ; FI. Dan. t. 2348, as R. hydrolapathum ; Reichenbach 
Iconogr. Crit. t. 370, fig. 5 54 > as L. hydrolapathum ; Beck in Reichenbach Icon, xxiv, t. 165 as R. hydrolapathum- 
Camb. Brit. FI. ii. Plate 142. ( a — d). 
Exsiccata : Billot, 3768, as R. hydrolapathum ; Fries, vi, 52, as R. aquations ; Herb. FI. Ingric. viii, 532 as 
R. hydrolapathum. 
Laminae narrower than in var. latifolius ; of the ground-leaves, more or less cuneate at 
the base, not cordate ; of the stem-leaves, broad at the base ; of the inflorescence-leaves cuneate 
at the base. Fruiting segments broadly triangular, about 4 — 5 mm. broad, entire or subentire ; 
tubercles broader than in var. latifolius. 
This is the common British form of the species. 
if) R. hydrolapathum var. latifolius [Borrer MS., ex] Trimen in Journ. Bot. xii, 35 (1874)!; R. maximus 
Schreber in Schweigger et Koerte FI. Erlang, i, 152 (1811) non Gmelin ; R. heterophyllns Schultz Prodr. FI. 
Starg., Suppl. 21 (1819); Rouy FI. France xii, 74 (1910); R. acutus var. latifolius Wahlenberg FI. Suec. 223 
(1824); R. aquations var. heterophyllns G. F. W. Meyer Chlor. Hanov. 477 (1836); R. aquations x hydrolapathum 
Haussknecht in Mitt. Geogr. ( Thiiring .) Jena iii, 64 (1885); Murbeck in Bot. Notiser 10 (1899); Ascherson 
und Graebner Syn. iv, 740 (1912). 
leones: — Sv. Bot. t. 161, as R. acutus ; FI. Dan. t. 2347, as R. maximus ; Trimen in Journ. Bot. xii, 
t. 140, as R. maximus ; Beck in Reichenbach Icon, xxiv, t. 169, fig. 3 — 8, as R. aquations x hydrolapathum. 
Camb. Brit. FI. ii. Plate 142. (e). 
Exsiccata: — Fries, vi, 53, as R. maximus ; Thielens et Devos, iii, 273, as R. maximus. 
Differs from var. vulgaris chiefly in its broader laminae. Laminae of the ground-leaves ovate- 
acute to deltoid, broader especially 
towards the base, shorter, at the 
base cordate, truncate, or rounded, 
often oblique, more or less obtuse at 
the apex ; of the stem-leaves, usually 
cordate at the base ; of the inflorescence 
broadly lanceolate, acute at the apex. 
Fruiting segments triangular, subcordate 
at the base, up to 7 mm. long and 6 to 7 
broad, margin more or less denticulate 
towards the base or subentire, each with 
an ovate-lanceolate acute tubercle. Seed 
elliptical acute, about 2^5 to 3 mm. long 
and 2 broad, chestnut-brown. 
English specimens of this variety often have 
the laminae more triangular than in the continental 
ones, and the tubercles more prominent. Otherwise, English and continental specimens are identical; and there need be 
no doubt that the var. latifolius of Trimen is the plant known abroad as R. maximus or as R. aquations x hydrolapathum. 
As to the status of the plant, there is much difference of opinion. Some botanists consider it a species, closely allied 
with but distinct from R. hydrolapathum ; but, in our opinion, the differences between the two plants are too slight to 
justify this view. Many authorities regard it as a hybrid of R. aquaticus and R. hydrolapathum ; but its occurrence in this 
country, where R. aquaticus is unknown 1 , is sufficient evidence for the rejection of this hypothesis. It may well be that 
hybrids of R. aquaticus and R. hydrolapathum occur in localities where these species grow side by side : if so, it is necessary 
to distinguish them from R. hydrolapathum var. latifolius. Rouy suggests that if the plant really be a hybrid, R. patientia 
or R. longifolius is more likely to be one of its parents than R. aquaticus. In answer to this suggestion, it is only necessary to 
point out that R. patientia (like R. aquaticus) is not a British plant, and that R. longifolius is unknown in Great Britain south 
of Derbyshire whilst the disputed plant (R. hydrolapathum var. latifolius - R. maximus) is confined to localities in the 
extreme south of England. 
Borders of rivers, ponds, and ditches ; rare and local ; Isle of Wight, Hampshire, Cornwall, Sussex, Surrey, 
Wiltshire, Suffolk. 
Scandinavia, Denmark, Germany, Holland, Belgium, France, Spain, Italy, central and southern Russia. 
Trimen ( loc . cit.) adds Cape Verde Islands, Azores, Formosa, and doubtfully from America. 
1 The statement by Ascherson and Graebner (Syn. iv, 735 (1912)) that R. aquaticus occurs in the British Islands is 
apparently based on a misapprehension. 
