Bulletin - United States National Museum - Smithsonian Institution

26 FLORA OF WASHINGTON AND VICINITY.
tive spot Sarraccnia purpurea^ Viola lanceolata^ and Carex hullata^ the
two first wholly unknown elsewhere, have been discovered ; a marsh a
mile above Bladensburg, near the mill-race, where only the majestic
Stenanthium rohustum has been seen; a little swamp near the Sligo
Creek, between the Kiggs and Blair roads, where the Hartford Fern
(Lygodium palmatum) grows sparingly; and another, between Bladens-
burg and the Maryland Agricultural College, where Solidago elliptlGa,
Ascyrum stans, and Lycopodium complanatum, var. Sabinwfolium, have
been found. The Eastern Branch region is not specially rich in floral
treasures, but on its banks and marshes some good things appear.
Steironema lanceolatum, Eleoclmris quadrangulata, ^cirpus JluviatiUs and
S. sylvatieiis, Ranunculus amhigens, and Salix Busselliana are among
these, though some of them are also found elsewhere.
V. FLOWERING TIME OF PLANTS.
It has already been remarked that most species flower at Washington
much earlier than at points farther north or than the dates giv^en in the
manuals. In consequence of this, a botanist unacquainted with this fact
and accustomed to those climates, and to relying upon the books, would
be likely to be behind the season throughout the year and fail to get
the greater part of the plants he desired. With all my efforts to make
allowance for this fact, I have frequently been sorely disappointed, and
was at last driven to making a careful record, preserving and correcting
it from year to year, of the flowering time of plants in this locality.
The notes on this subject appended to nearly every species enumerated
in the list embody the general results of these observations, and may in
the main be relied upon. The expressions used are not loose conjectures,
but are in the nature of compilations from recorded data. In most cashes
an allowance of two weeks may be made for the difference in seasons,
though rarely more and often less. Certain plants, as, for example,
Tipularia discolor, flower at almost exactly the same time every year.
Occasionally, however, one will vary a month or more in a quite unac-
countable way. But any one who has watched the periodical changes of
the general vegetation for a series of years and recorded his observations
will more and more realize the exactness even of these complex biological
phenomena, which depend so absolutely upon uniform astronomical
events.
From this point of view the season which presents the greatest varia-
tion, and also for this and other reasons the greatest interest, is the