A very interesting Bulletin of eight pages on the Chrysanthemum Rust
has been issued by J. C. Arthur, botanist of the Indiana Agricultural
Experiment Station. It is No. 85, and is dated October, 1900. Dr.
Arthur gives a general account of Uredineae or Rusts, explaining
that the typical forms have three prominent sets of spores, namely
(1) aecidiospores, usually red or orange in little white cups, (2)
uredospores, generally of a rusty yellow color and abundant (hence
the group name, Rusts), and (3) teleutospores, or the Winter spores,
usually dark brown or black. He further states that only uredospores
have yet been found in Europe and America, and since the fungus is an
annual, it is puzzling to see how it escapes extermination in winter
and spring when Chrysanthemum plants are latent.
The assumption that this was the well known and common Puccinia
hieracii or Puccinia tanaceti he proves to be incorrect by inoculation
experiments. Uredospores from Chrysanthemums he sowed on Chrysanthemums
and obtained a crop of uredospores. Similar uredospores sowed on
Dandelion, Burdock, and Ox-eye Daisy produced no infection; uredospores
from the latter hosts sown on Chrysanthemum likewise produced no
infection. Uredospores from Dandelion sown on Dandelion produced
uredospores. Others have tried similar experiments, using Tansy,
Costmary, Orange Hawkweed, Giant Daisy, and Marguerite, besides the
host plants named above, but the Chrysanthemum Rust refuses to grow
on any of them. This Rust, which is common and well known on the
Chrysanthemum in Japan, has been named Puccinia chrysanthemi by Rose.
In connection with suggestions relative to combating the disease,
Dr. Arthur says that “so long as the teleutospores do not make an
appearance in this country, the careful cultivator may feel assured
that a moderate amount of timely effort will enable him to rid
his establishment of the Rust, if he is so unfortunate as to have
it donated to him by some careless florist. Observations made by
the writer and others show that the tendency is for the disease
to disappear of itself, to run its course in an establishment and
die out, which is very likely to some extent due to the absence of
teleutospores.”
BRYOLOGY.—Mrs. Britton’s popular articles on the Mosses and how to
study them, that have appeared from time to time, furnished the
directions and incentive to many who before had taken little or no
interest in this group of plants. Her purpose and plan are imitated
and extended in a charming little book, that has been prepared and
published by Dr. A. J. Grout, of the Boys’ High School, Brooklyn, New
York, called “Mosses with a Hand-Lens.” The author says that many years
of study of Mosses in the field and in Herbaria have convinced him
that “any person of average intelligence can easily learn to recognize
seventy to one hundred common mosses, with the aid of a hand-lens of
ten to fifteen diameters magnifying power.”
[Illustration: Fig. 9, Ceratodon.]
I have Dr. Grout’s permission to reproduce two illustrations, which
represent fairly that phase of his valuable book. Figure 9 shows
Ceratodon purpureus L, and the text pertaining to the same is as
follows: “Ceratodon is one of the commonest of all our mosses. It
is found on the edges of paths, roofs of old buildings, sand by the
seashore, and in general any barren compact soil is its favorite
habitat. The plants are short and grow close together, forming dense
thin mats of dark green. The lance-like young sporophytes appear early
in spring as soon as the snow is melted. By the middle of summer the
capsules often decay beyond recognition, and the seta breaks from the
plant at the touch.
Unless one has become very familiar with Ceratodon it is not always
easy to recognize it without mature capsules. When the capsules have
fully matured they shrink when dry and become furrowed. This peculiar
furrowing, the dark rich color of the capsules, a color called purple
by the older botanists, but which is really a very dark chestnut or
red-brown, make it easy to recognize this species.”
Plate II. shows the Hair-cap Mosses, Polytrichum, the largest of all
our species. There are four common species all having square capsules
which character distinguishes them from Pogonatums, the latter having
cylindric capsules. “The Ohio Hair-cap without the sporophyte (seta
and capsule, commonly called fruit) is not readily distinguished from
the Common, as the leaves and general appearance are very similar. But
with the sporophyte present, the distinctions are clear. In Figs. b and
d (Plate II.) note that the capsule of the Common Hair-cap is almost
cubical, that the lid has a _very short beak_, and that the capsule is
entirely covered by the calyptra. The capsule of the Ohio Hair-cap (e)
is elongated, slender with a tapering neck, and with a much longer beak
to the lid. The lid and the calyptra of the Ohio Hair-cap fall early in
June, very soon after the spores are ripe, and it is not always easy to
find either in position, but if the calyptra be found, it will be seen
to cover the upper portion of the capsule only. The Common Hair-cap,
although occurring in woods, is most common in open fields; the Ohio
Hair-cap being most frequent in shady, more moist spots, often in deep
woods. The remaining two species are easily distinguished from the
two mentioned above by the margins of the leaves, which are thin and
membranaceous, and are folded in over the central portion of the leaf,
as illustrated in o, o′ and p.”
[Illustration:
Plate II., Polytrichum or Hair-cap Moss.
Figs. a (dry), b (moist), c (leaf), d (capsule) and f are P. commune;
Fig. e, capsule of P. ohioense;
Figs. g, h and p, P. piliferum;
Figs. o and o′, P. juniperinum.]
I can not too strongly commend “Mosses with a Hand-Lens” (price $1.10)
prepared with the purpose of giving “by drawings and descriptions the
information necessary to enable any one interested to become acquainted
with the more common mosses with the least possible outlay of time,
patience and money.” The book contains a key to the genera based mainly
on structural characters and one mainly on habitat, also many keys
under the genera; copious illustrations, clear and accurate on almost
every page of the text and eight full-page plates from drawings by Mary
V. Thayer; and an illustrated glossary of bryological terms.