RANUNCULI: s.] RANUNCULACE^E. 5 



achenes. DISTRIB. All temp, regions ; species about 160. ETYM. rana y 

 a frog. 



SECTION 1. Batra'chium. Water- or marsh-plants. Leaves often sub- 

 merged and multifid ; stipules membranous. Peduncles usually leaf- 

 opposed, 1-fld. Flowers proterandrous. Petals white ; gland naked, 

 yellow, basal. Achenes transversely wrinkled. 



The following is an attempt to group naturally the British BatrachianTfa wimcwfo', 

 after a protracted study of the large collection at Kew (Herb. Kew, H. C. 

 Watson, Borrer, Bot. Exch. Club, G. Nicholson, &c.). The result accords 

 in a measure with the early views of H. C. Watson (Suppl. to Cybele, 1860 ; 

 and Companion to ditto, 1868). Opinions vary as to whether the 8 forms 

 or even segregates of them should be ranked as one or more species, sub- 

 species, or varieties ; I regard them as approximately equivalent to the 

 species I have retained under Rubus, Rosa, &c. Of the characters attributed 

 to these and their subordinate forms by critical authors, I find some variable, 

 others valueless, and still others deceptive ; such especially as concern the 

 tapering,' &c., of the peduncle, the comparative length of stamens and petals, 

 number of stamens, and especially the forms of the receptacle, achenes, and 

 stigma. 



* Aquatic. Floating leaves usually present; submerged numerous, multifid. 

 Petals 5-9-nerved. Receptacle hispid. 



1. R. heterophyl'lus, Fries ; segments of submerged leaves spreading in 

 all directions, peduncles hardly exceeding the leaves, flowers ^-1 in. 

 diam., petals broadly obovate, stamens numerous. JR. aqua'tilis, Sm. 



Streams and ponds from Orkney southd., ascending to 1,050 ft. in Scot- 

 land ; Ireland ; Channel Islands; fl. May-June. Floating leaves (rarely 0), 

 |-1| in. diam., from orbicular to reniform, 3-5-lobed or -partite or 3-foliolate ; 

 basal sinus broad or narrow, segments broadly cuneate, toothed, lobulate, or 

 laciniate ; stipules broad, rounded. Petals much longer than the sepals. 

 Stamens longer than the pistil. Achenes glabrous or hairy or hispid ; stigma 

 short, obtuse. DISTRIB. Europe (Arctic), N. America, N. Asia. R. hetero- 

 phyl'lus proper; segments of submerged leaves collapsing into a tassel 

 when removed from the water, flowers about in. diam., achenes usually 

 glabrous. R.pelta'tus, Fries (R. foribun'dus, Bab., R. trunc'atus, Dumort.), 

 has segments of submerged leaves more rigid, flowers |-1 in. diam., petals 

 broader, achenes usually hairy or hispid. R.jissifo'lius, Schrank, is a form 

 with laciniate leaf-lobes (Loch Maben, &c.). R. penicilla'tus, Dumort. (R. 

 pseudo-Jluitans, Bab.), is a remarkable form with the habit, long robust 

 stem and long leaves and peduncles, and large flowers of Jluitans, but the 

 hirsute receptacle of heterophyl'lus ; it forms the passage between the two. 

 From Derby and Warwick, to Wilts and Surrey ; Ireland. R. triphyl'los, 

 Wallr., from Guernsey, an imperfectly known plant, may be a form of 

 heterophyl'lus. 



2. R f mari'nus, Fries ; segments of shortly petioled submerged leaves 

 spreading all round, peduncles much longer than the leaves, flowers -f 

 in. diam., petals narrowly obovate, stamens few or many. It. c 



var. Symei, Hook, and Arn. 



