NEW SPECIES OF RANUNCULUS 335 



virens, nullo modo nitens, at quasi leviter glaucescens. Folia 

 radicalia pro planta parvula, longe petiolata, pelerumque rotundato- 

 reniformia, 2-3 cm. lata, crenata; caulina inferiora radicalibus 

 majora, breviter sed distincte petiolata, profunde trisecta, segmentis 

 cuneato-flabelliformibus vel anguste rhomboideis, supra medium 

 plus minus distincte crenatis vel dentatis, suprema sessilia, tri- 

 partita, segmentis oblongis integris. Flores minimi. Capitula 

 globosa. Achaenia modice compressa et stylo brevissimo acuto 

 recurvo apiculata. 



First observed by me as growing on a railway embankment 

 near Linden Station of the Baltimore and Ohio Railway, within 

 the State of Maryland, but not far outside the District of Columbia, 

 this in May, 1912. Then a few weeks later I saw it growing in 

 great profusion along the line of the same railway quite within 

 the District, namely, on the outskirts of Tacoma Park eastward. 

 It grows there in abdunance in the most exposed places, partic- 

 ularly about piles of brush-wood or other rubbish. In respect to 

 its peculiar habitat, as well as by many diagnostic characters, it 

 is in strong contrast to the less common R. abortivus, the leaves 

 of which are thrice as large, besides being readily distinguished' 

 always by their deep-green color, with a polished and shining 

 surface; and this, the real R. abortivus inhabits only rich soil, 

 entirely in the shade of woods, or if within city limits, in like 

 shaded proximity to walls and buildings. 



R. ruder alis is, indeed, next of kin to R. Allegheniensis, which 

 it much resembles in the small size and light shade of leaves, 

 without a trace of that lustre characteristic of R. abortivus alone; 

 but while the achenes of R. Allegheniensis are tipped with a long 

 and conspicuous style, those of R. ruderalis end so bluntly as to 

 seem to have no style at all, and a lens is requisite to reveal 

 their presence. 



The fact of its having been found by me nowhere but in 

 proximity to a line of railway that runs westward half across the 

 continent should have suggested to me the possibility of its being 

 in this part of the world only as an immigrant from the West; 

 yet the thought did not occur; therefore it was with surprise that 

 I observe it a year later, in the prairie region of the Middle West, 

 and saw that it was clearly native there, where the botanists 

 of that region, never having known the real R. abortivus, called 

 it always by that name. 



