|BOTANICAL ELECTRONIC NEWS|
|No. 162 April 9, firstname.lastname@example.org Victoria, B.C.|
In August of 1994 while botanizing the northern part of Burns Bog [south of Vancouver, B.C.], near the area where the Eriophorum virginicum has been introduced, I noticed large populations of what appeared at a distance to be Racomitrium heterostichum. They grow on what is otherwise bare peat. Closer inspection showed apical hairpoints diverging horizontally, as they do in C. introflexus. Microscopic examination of leaf cross sections also indicated a Campylopus. Dr. Wilf Schofield confirmed my previous speculation when I gave him the collection. Last year a population was also found in the Big Bend Bog in Burnaby and fertile material was also collected at another site in Burns Bog.
Campylopus introflexus (Hedw.) Brid. is an introduction from the southern hemisphere and had not been collected previously in Canada, although it does occur along the Oregon coast.
The introduction of bryophytes to the British Columbian flora has not significantly enriched the flora. This is in strong contrast to the vascular plants, in which introductions are reported to form over 20% of the vascular flora.
Apparent introductions are characterized by the fact that their presence in the province is discordant with their natural world distribution.
Some bryophytes associated with disturbed soil appear to be introductions because they are unknown from undisturbed sites. In the B.C. flora Micromitrium tenerum, Orthotrichum diaphanum, Physcomitrium immersum, Pottia truncata, Pseudephemerum nitidum and Tortula amplexa could well be introductions, but it is impossible to be confident.
Other species common in the indigenous flora are obviously spread by human activity, especially in the production of extensive disturbed sites near roads and gardens. Mosses that fit this category include Atrichum undulatum, Barbula unguiculata, Calliergonella cuspidata, Ceratodon purpureus, Funaria hygrometrica, Leptobryum pyriforme, Rhytidiadelphus squarrosus and Tortula muralis as well as many others, plus the liverwort Marchantia polymorpha.
In lawns, especially in urban areas, several mosses are favoured by the conditions maintained through lawn-mowing and fertilization, as well as winter conditions of the lawn. Some mosses, including several species of Brachythecium (largely undeterminable, and possibly exotic in origin), Rhytidiadelphus squarrosus, Calliergonella cuspidata and Pseudoscleropodium purum often form extensive carpets. It is possible that these mosses are transported accidentally from one lawn to another by lawn maintenance workers. In the final mowing in autumn, the mosses are usually of a stature that allows them to be fragmented by the lawn mower. These fragments adhere to the mower and are, in consequence, transported to another lawn where they detach and are scattered. During the winter, when the grass is dormant, the moss fragments are able to flourish and grow under the favourable light and moisture conditions and produce extensive carpets. Moss killers applied in the spring can destroy most of these, but if any living plants persist, they are fragmented as the lawn is mowed, and the next winter repeats the process.
The bryophyte introductions appear to have originated with horticultural plants. Pseudoscleropodium is often used as packing material for nursery stock in Europe, where the species in native to the flora. It is probable that this was transported out of Europe through this means. In both eastern and western North America it is confined mainly to lawns, although in B.C., at lest, it is known from near coastal cities (Vancouver, Victoria, Nanaimo), but is also on Galiano Island and probably elsewhere. It has also been introduced to Australia and New Zealand as well as other non-European localities. Pseudocrossidium hornschuchianun, Pottia truncata, Physcomitrium immersum, and Lunularia cruciata are associated almost exclusively to gardens or to the perimeter of agricultural land, and sometimes persist briefly in a site. It is reasonable to speculate that these originated with soil in pots of garden seedlings.
The introduction of Campylopus introflexus (endemic to the Southern Hemisphere) and Orthotrichum diaphanum are difficult to explain. The Campylopus is confined in B.C. to Burns and Bend Bogs in the Lower Mainland, to disturbed peatland. It is known in western North America also from Oregon (sand dune slacks), and adjacent California (seemingly natural habitats). This Campylopus was introduced to Europe many years ago and has spread relatively rapidly. Terry Taylor has discovered both fertile and vegetative populations, sometimes, covering extensive tracts. The plants are brittle, and the fragments can readily establish the species in new sites after transfer. The Orthotrichum is indigenous to North America, but the only B.C. sites are in Vancouver (concrete walls and introduced cottonwood trees). The species is not common in western United States, so its appearance in Vancouver in anthropogenic sites is mysterious.
The intriguing problems remain concerning the vegetative populations of several species of Brachythecium in lawns. Some are extremely abundant. Sporophytes are essential for confident determination. Lawn mowing appears to impede sporophyte production, keeping the populations in a vegetative state. sp It is apparent that introduced bryophytes harbour many intriguing problems worthy of attention.
Ordering information: Order from University Press of Colorado, P.O.Box 849, Niwot, CO 80544. Toll-free number 1-800-268-6044. $US39.95, shipping $3.00 for first book, $1.00 for each additional.
Charles Christopher Parry is well known to botanists worldwide. More than eighty new species of flowering plants were named from Parry's Colorado collections, and many more from his collections in Mexico and the American Southwest. Fascinated with mountains, Parry made barometric observations that permitted the first accurate estimations of altitudes of the high peaks. Yet his greatest contribution to science was through the distribution of his botanical collections to the museums of the world. Except for his name having been affixed to many of Colorado's wildflowers, two mountain peaks, and a creek in Middle Park, he is hardly known in Colorado. . . . [The book] combines the lists of Parry's collections with the scientific and semipopular descriptions of his travels, up till now found only scattered in rare periodicals and old newspapers. This is a work that will be of interest to naturalists and all others interested in the West as it existed during Parry's lifetime.
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BEN is archived on gopher freenet.victoria.bc.ca. The URL is:
gopher://freenet.victoria.bc.ca:70/11/environment/Botany/ben. Also archived at http://www.ou.edu/cas/botany-micro/ben/