GEUM CANADENSE FLAVUM (PORTER) BRITTON A VALID SPECIES.
This plant is clearly an excellent species and should stand as Geum fiavunz (Porter). It is common in the vicinity of New York and shows itself to be perfectly distinct from its near relative, Gam Canadense Jacq., with which it is often found associated. Its points of difference from the latter are by no means confined to the size and color of the petals, but involve the pubescence, the form and texture of the leaves the branching of the inflorescence and other less obvious features. As these characters have never been pointed out, it may be useful to draw attention to them.
Geum fiervunz is much more coarsely pubescent below than Can adense, in which the basal petioles and lower part of the stem are often glabrate or only sparsely pubescent ; in flavum the lower stem is hirsute-pubescent, often equally so with Geum Virginzanum L., the leafstalks spread i ng-villose.
The leaves of flavum are mostly larger, thinner and duller green than in Canadense, often becoming very large and lax. The largest in specimens before me are 8' long by 7' wide on petioles 3' in length, dimensions which greatly exceed anything seen in Canadense. The long-petioled basal leaves at flowering time are exceedingly multiform, varying from cordate-orbicular through trifoliate to pinnate with two or three pairs of leaflets, show ing a much readier tendency to a pinnate form than those of Canadensc and to the development of small subleaflets on the peti ole. The lower cauline leaves reveal the same tendency to greater subdivision than those of Canadensc, which are rarely other than trifoliolate or subpinnate. In _Amin they are usually dis tinctly pinnate with 3-7 leaflets, the odd leaflet elongated and ob liquely pinnatifid or pinnately-parted into oblong decurrent lobes ; the lowest pair of leaflets are frequently also pinnatifid. In the trifoliolate stem-leaves of flerzwin the end leaflet is much longer rel atively to the lateral ones than is the case in Canadense, and the simple upper leaves are mostly oblong or narrower with often ob tuse basal lobes, usually in marked contrast with those of Cana dense, which are rhombic-ovate or obovate and cuneate with acu minate or very acute lobes or angles mostly at or above the middle.
Thr dentition o the leaves in Arvin/ is coarser than in especially in the upper leaves, which are very coarsely dentate with irregular shallow teeth, in striking contrast with the much more finely and acutely dentate-serrate leaves of the latter.
The stipules offavitin are conspicuously larger than those of Canadense and variously incised and lobed ; an extreme size is 1W long by broad ; the largest on specimens of Canadense now before me are 8" x 4". The pubescence of the leaves is in favum coarser and looser than in Canadense, especially along the veins on the lower side of the basal leaves ; it is much sparser on the upper leaves which are sometimes glabrate; in Canadense the leaves beneath are finely soft pubescent and velvety to the touch.
Whileflavum is generally more slender and weaker than Cana dense this is not always true, except perhaps of the inflorescence, which is simpler and fewer-flowered with longer, more ascending branches and peduncles, the bracts often more foliaceous and sometimes entire.
The flowers of the two plants are always conspicuously different and constitute their most obvious distinctive character. In flavkin the very small petals are cream-color or palest yellow and much shorter than the lobes of the calyx, i"—i long, wide, linear-oblong or often broadened to the abrupt or truncate often retuse tip ; in Canadense they are pure white, oblong or obovate, and two to four times as large (2"-4" long, i wide) equal ling or exceeding the calyx-lobes. In both species the anthers show a shade more color than the petals. The flowers differ urther in the sepals, which in Canadense are more accuminate, and in the bractlets of the calyx, which are rather larger in favkm. In the latter the flowers are at first nodding ; in Canadense they are erect or sometimes a little declined.