BEN |
BOTANICAL ELECTRONIC NEWS |
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ISSN 1188-603X |
No. 232 September 17, 1999 | aceska@freenet.victoria.tc.ca | Victoria, B.C. |
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Scientists in the US Forest Service Olympia, Washington have initiated a study of Oregon white oak/Garry oak acorn production. They are looking for volunteers to survey oak trees for acorn abundance in September and October this year and in future years. Survey forms, instructions and additional information on this species can be found on the following web page:
Of the circumpolar species of cranberries, Vander Kloet (1983) recognized only one broad species, Oxycoccus palustris Pers. Other authors considered the wide heterogeneity of this complex and segregated the diploid (2n=24) as a separate species - Oxycoccus microcarpus Turcz. ex Rupr. Based on the chromosome numbers, the hexaploid (2n=72) has been sometimes treated as an additional separate species, Oxycoccus hagerupii Love & Love (Ahokas 1971a, 1971b, Gugnacka-Fiedor 1983, 1986, Ravanko 1990, Wenderoth & Wenderoth 1994). These authors follow the narrowest concept where Oxycoccus palustris s. str. is restricted to the tetraploid plants with 2n=48.
I have conducted my research of cranberries in mountain regions of the Czech Republic and I have come to the following conclusions (Suda 1998):
Native in eastern North America, and adventive in Europe and in western North America where it has escaped from cultivation.
Circumpolar species with more northerly distribution than O. palustris. Oxycoccus microcarpus can be distinguished from O. palustris by having shorter corolla, shorter stamens and styles, by filaments that are longer than the relatively short anthers (measured without tubular horns), by smaller seeds, and above all by mostly single flowered, glabrous pedicels. These two species also differ in the size of their leaves and in their phenology: where both species occur together, O. microcarpus flowers about 2-3 weeks earlier than O. palustris. Oxycoccus microcarpus grows most often in cushions of Polytrichum strictum, or in hummocks of Sphagnum fuscum or S. compactum. It prefers elevated, not shaded habitats free of any herbaceous vegetation. Wenderoth & Wenderoth (1994) did not find any instance of O. microcarpus growing together with O. palustris. During my field work in the Czech Republic, I found these two species growing together quite often.
In the Czech Republic this species occurs in three ploidy levels that can be morphologically separated with great difficulty. Reliable identification of the ploidy level of single plants is impossible. One has to measure larger number of plants and use averages from about 30 individuals. With the use of these average values one can assign the measured population to a certain ploidy level.
Key to the identification of ploidy levels of Oxycoccus palustris based on average values of the population.
Tetraploid cytotype (2n=48)
Tetraploid plants occur in southern Bohemia in the Trebon area and they are common in northern parts of Bohemia. Because of the occurrence of pentaploid cytotype in the Sumava Mtns., the tetraploid cytotype is expected to occur there as well.
Pentaploid cytotype (2n=60)
I was the first one to report this pentaploid level from the Sumava Mtns. and from northern Bohemia (Suda 1998). The plants of this ploidy level are most probably of hybridogenous origin. The most reliable character to detect this ploidy is a high proportion of aborted pollen tetrads. Additional characters are relatively long filaments and smaller leaves with strongly involuted margins. The seed production is lower than in other ploidy levels, but the seed germination is about the same as that of other ploidy levels.
Hexaploid cytotype (2n=72)
Hexaploid cytotype (occasionally treated as a separate species - O. hagerupii Love & Love) is the most common cytotype in the Czech Republic. To distinguish hexaploids from tetraploids is possible only in the flowering plants. Plants of both ploidies differ only in quantitative characters (size of the corolla, length of the style, and length on bracts and bracteoles). The size of seeds (especially their width) is an important distinguishing character in fruit bearing plants.
References:
From: Rudi Schmid <[schmid@socrates.berkeley.edu] - originally published in Taxon 48: 631 (August 1999)
I asked Randy Wilson, reference librarian in the Biosciences Library at UC Berkeley, and also the person responsible for book acquisitions there, for the general URLs that he finds most useful to access publishers. His answer is below: Another worthwhile URL is that of of the Association of American University Presses: http://aaup.pupress.princeton.edu/ This allows one to search all the catalogs of the individual publishers. Two other helpful bookseller URLs are http://www.ledlie.com/ of Patricia Ledlie Bookseller (U.S.) [Comment added 9/99: The Ledlie WWW site will end by 1 Jan. 2000] and http://www.nhbs.com/ of Natural History Bookstore (U.K.).
- Rudi Schmid
These are the five (actually seven) sites that I use most often, when I'm not using Books in Print (BIP), which is available online at MELVYL, the digital library catalog for the University of California and other academic libraries (it is unavailable to single users directly online). I've listed them by my frequency of use.
There are many more sources out on the Web, but these are the ones I use most often. I will add one more URL, for Osiander, a bookseller in Germany. I've hardly used it, but it has been helpful those few times: http://www.osiander.de/gb/home.html
Randy Wilson [rwilson@library.berkeley.edu], BIOS, University of California, Berkeley, CA