450 REPORT OP NEW JERSEY STATE MUSEUM." 



//. Head of fruit elongate, beak of achene 



straight. R. pennsylvanicus, p. 456 



hh. Flowers large and showy, 15-3° mm. broad. 



t. Beak of achene short, plants of fields, 



roadsides and waste ground. 



j. Root fibrous, calyx spreading. 



[R. acris]* 



}'}'. Stem buIBous at base, calyx reflexed. 



[R. bulbosus]-^ 



ii. Beak of achene long, plants of woods or 



swamps. 



y. Beak stout, later branches prostrate, 

 rooting at the nodes, shaded damp 

 ground. R. septentrionalis, p. 456 



jj. Beak slender, plants upright, in wood- 

 lands. R- hispidus, p. 457 

 ee. Achenes transversely wrinkled, flowers white, plants float- 

 ing in water, leaves finely divided. 



Batrachium trichophyllum, p. 457 



eee. Achenes compressed and longitudinally ribbed, plants low, 



glabrous (4-20 cm.) spreading by runners, flowers small 



yellow. Oxygraphis cymbalaria, p. 457 



dd. Petals none, flowers forming large, feathery, open panicles, 



greenish or white. 



e. Filaments of the stamens club-shaped, plant not glandular. 



ee. Filaments capillary. T. polygamum, p. 458 



f. Plants low, 3-6 dm., flowers dioecious greenish, leaves 



thin. T. dioicum, p. 458 



ff. Plants tall, 10-20 dm., flowers polygamous, white, 



leaves thick and glandular or waxy. 



T. revolutum, p. 458 

 CALTHA L. 

 Caltha palustris L. Marsh Marigold. 



Caltha palustris Linnaeus, Sp. PI. 558. 1753 [Europe]. — Barton, Fl. Phila. II. 

 216. i8i8.-^Willis 3. — Britton 38. — Keller and Brown 147. 



Comiri'on in swamps in the northern counties and less abundant 

 locally southward in the Middle district. 



F/. — lEarly April to early May. Fr. — ^L,ate May to late June. 



Middle District. — Freehold (C), Keyport, Perrineville (C), Parmingdale, 

 New Egypt, Bordentown (C), Pensauken, Medford (S), Cooper's Creek, 

 Camden (Bassett), Kaighns Pt., Lindenwold, Mantua, Mickleton, Manning- 

 ton (C), Swedesboro. 



* Tall Buttercup. The common roadside species in the northern part of 

 the State, not common in our region. 



t Bulbous Buttercup. The common Buttercup of fields and meadows, an 

 abundant weed. 



