Bulletin - United States National Museum - Smithsonian Institution

Rumex verticillatus, L.
FLORA OF WASHINGTON AND VICINITY. 109
Above Sandy Laudiug. Juue, July.
t Rumex c?-ispu8, L. Curled Dock.
Juue.
t Rumex ohtusifolius, L. Bitter Dock.
May to July.
Rumex crispuaxobtusifolius, Gray, Manual, ed. 5, p. 421.
This well-marked hybrid is this year abundant in the city reservation west of the
Capitol, between Four-and-a-half and Sixth streets, where it may be easily compared
with l)oth the parent species. It may be roughly described as having the narrow
leaves of li. crisjJMS, though less wavy-margined, and the toothed valves of B.
obtusifoUus, this character being, however, less evident on the uon-grain-beariug
valves. The habit of the hybrid is quite distinct from either, beiug more symmetrical
and less ugly. The tendency seen in li. ohtusifolius to exhibit red midribs and
speckles on the leaves is exaggerated in the hybrid.
tRumex Acetosella, L. Field Sorrel. Horse Sorrel.
Last half of May.
PODOSTEMACEiE.
Eiver-weed Family.
Podostemon ceratophyllus, Michx. River-weed.
Rock Creek, below Lyon's Dam ; Difficult Run. June, July.
ARISTOLOCHIACEiE.
BiRTHwoRT Family.
t Asarum Canadense, L. Wild Ginger. Asarabacca.
Last of April or first of May.
t Aristolochia Serpentaria, L. Virginia Snakeroot.
Widely distributed, but nowhere abundant. June.
f Saururus cernuus, L. Lizaed's Tail.
July.
t Sassafras officinale, Nees.
PIPERACE-ffJ.
LAURA-CEiE.
Laurel Family.
April. For an attempt to explain the significance of the rudimentary organs of
Sassafras, Lindera, and other Lauraceous plants, see my paper on " Homologies in
the Lauraceai," read before the A. A. A. S. at Saratoga, and published in the Scien-
tific American, Supplement, of Seftember 20, 1879, p. 3083.
t Lindera Benzoin, Meisner. Spice bush. Benjamin-bush,
March, April.
THYMELEACEiE.
Mezereum Family.
Dirca palustris, L. Leather-wood. Moose-wood.
Second or third week in Aiiril.