Chromosome Studies on Some Mosses of Ontario and Québec

Abstract

Meiotic chromosome studies were made on 18 species of Ontario and Quebec mosses in 14 genera and 12 families. The chromosome number of Orthotrichum stellatum Brid. (n = 10 + m) is reported for thefirst time. The number n = 14 is reported for Quebec plants of Trematodon ambiguus (Hedw.) Hornsch. which differs from the only other recorded number of n = 13 + 2 for the species. The first chromosome counts for North American populations of Brachythecium salebrosum (Web. & Mohr) B.S.G., Leucobryum glaucum (Hedw.) Aongstr. ex Fr., and Orthotrichum anomalum Hedw. are reported. Up to 1980 only approximately 1,300 of nearly 14,000 moss taxa known in the world had been investigated cytologically (Fritsch 1982). While there have been some studies during the 1980's, at present there still remain entire families cytologically unstudied, e.g., Dicnemonaceae, Gigaspermaceae, Hydropogonaceae, Lepyrodontaceae, Phyllogoniaceae, Rutenbergiaceae, and Spiridentaceae. In addition, some of the studies have been based on only a single population or even just a single plant. The studies have been made mostly on mosses from European countries, especially Great Britain and parts of the U.S.S.R., as well as the United States, Japan, Australia, and India. Very few studies have been made on mosses from countries in Latin America and Africa. Al-Aish and Anderson (1960) commented thirty years ago that Almost no cytological studies have been made of the mosses of eastern Canada. This same statement is equally applicable today. The only chromosome studies that have been conducted on the mosses of eastern Canada are those by Anderson and Bryan (1958) on two species from Qu6bec and three from Nova Scotia; Al-Aish and Anderson (1960) on five species from Quebec; Ireland (1969b) on one species from Ontario; Maass and Harvey (1973) on three species from Ontario, two from Newfoundland, and 21 from Nova Scotia; and Inoue (1979, 1981) on six species from Ontario. On the other hand, the mosses of western Canada have received somewhat more attention with approximately 100 species studied according to Ramsay and Schofield (1981). However, the total number of species studied cytologically throughout Canada epresents only about 14% of the 965 species known to occur in the country (Ireland et al. 1987). Besides the few species studied many of them have been examined from only a single population. The fact that there have been so few chromosome studies on mosses in Canada makes it worthwhile to study more species from this huge country in order to learn more about the chromosome numbers and behavior. MATERIALS AND METHODS Meiotic chromosomes of spore mother cells were studied in mosses with young sporophytes collected from several localities in Ontario and Qu6bec. Preparation of living plant material and cytological techniques follow methods recently described by Anderson and Bryan (1987). Both the 3:1 absolute alcohol: acetic acid fixative and the aceticorcein stain were employed as detailed in their study. Data are presented for 28 populations representing 18 species of mosses. Meiotic figures in several cells of each population were studied to determine chromosome number and behavior. Also, observations on meiosis in the spore mother cells in more than one capsule were made whenever possible. The systematic arrangement and nomenclature follow Ireland et al. (1987). Voucher specimens are deposited in the bryophyte herbarium (CANM) of the Canadian Museum of Nature in Ottawa, Ontario.