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A NEW HYBRID WATER RANUNCULUS. 



By H. & J. Groves, F.L.S. 



Plate 420. 



Some years ago we received from Mr. T. Hilton a curious water 

 Ranunculus, collected by him at Copthorne Common, East Sussex. 

 The upper leaves and the heads of carpels resembled those of R, 

 Lenotmandi, but the lower leaves were much divided though not 

 capillary, while in stature, and the shape and size of the flowers, it 

 resembled a small state of E. peltatus. Our first impression was 

 that it must be a hybrid between these two species, but the presence 

 of some well-developed heads of fruit seemed to militate against 

 this view, and we did not feel that there was sufficient evidence to 

 come to a conclusion, so put it aside among the many puzzles in 

 this group, to await further material for solution. 



On the 23rd of May of the present year Messrs. C. E. Saluion 

 and James Groves visited the locality, duly found the plant, and 

 collected a series of specimens. It occurred somewhat sparingly 

 in a rather muddy stream in company with R. Lenorniandl and a 

 fairly typical form of R. peltatus, but generally in deeper water than 

 the former. 



On examining a number of fruiting heads we found that a con- 

 siderable proportion of the carpels were undeveloped, and this being 

 the case, taken in conjunction with the facts that the plant occurs 

 in small quantity in company with both of the supposed parents, 

 and that it possesses some of the distinguishing characteristics of 

 each of them, we cannot resist the conclusion that it is a hybrid 

 between R. Lenonnandi and R. peltatus. Tlie plant is so distinct 

 and remarkable that we think it desirable to describe and figure it. 



R. Hiltoni, hibr. nov. {R. Lenormamli x peltatus). Stem rather 

 stout, rooting at many of the nodes; lower submersed leaves stalked, 

 once or twice trifurcate, with linear acute (not capillary) laciniaD ; 

 upper long-stalked, mostly semicircular-reniform, trifid (sometimes 

 tripartite), segments cuneate, deeply 3-5-lobed, lobes mostly acute; 

 floating leaves rather coriaceous, cordate-orbicular, with 3 rounded 

 lobes, the central lobe entire, or with two notches, the lateral with 

 1 deep and 2 shallow notches ; stipules large, lower acute, upper 

 broad rounded ; peduncle stout, usually longer than the subtending 

 petiole, recurved with fruit ; sepals ovate reflexed ; petals obovate, 

 claw but slightly yellow, nectary cup-shaped, or wanting ; stamens 

 about 12-14 ; carpels about 40, glabrous or slightly hairy, dis- 

 tinctly keeled, inner edge rounded towards the top. 



Discovered in April, 1896, by Mr. T. Hilton, in a stream on 

 Copthorne Common, East Sussex. 



R. Hiltoyii resembles R. Lenonnandi in its rooting habit, the 

 shape of the floating leaves, the number of stamens, and the usually 

 glabrous carpels with rounded inner edge ; while it approaches 

 R. peltatus in the shape and size of the petals and the hairy 



Journal OF Botany. — Vol.39. [April. 1901.] k 



