Chromosome Numbers of Some Mosses from Pennsylvania and New York

Abstract

Chromosome numbers for eight species of mosses from Pennsylvania and New York, USA, are reported: Barbula unguiculata Hedw. (n = 13 + 1 m), Pottia truncata (Hedw.) Fiirnr. ex B.S.G. (n = 26), Aphanorrhegma serratum (J. Hook. & Wils. ex Drumm.) Sull. (n = 27), Bryum argenteum Hedw. (n = 10), Brachythecium rutabulum (Hedw.) B.S.G. (n = 12), Callicladium haldanianum (Grev.) Crum (n = 22), Pogonatum pensilvanicum (Hedw.) P.-Beauv. (n = 7), and Atrichum altecristatum (Ren. & Card.) Irel. Chromosome numbers of eight species of mosses from Pennsylvania and New York are reported below. Methods followed are those of Steere et al. (1954). Observations and drawings were made with a Wild Heerbrugg Microscope and drawing tube. Voucher specimens have been deposited in the herbarium of The Pennsylvania State University (PAC). BARBULA UNGUICULATA Hedw., n = 13 + 1 m (Fig. 1). Pennsylvania, Centre Co., campus of The Pennsylvania State University, ca. 400 m alt., on soil, Lin 003. The population studied presented a chromosome count of 13 + 1 m (Fig. 1). The minute accessory chromosome sometimes stained poorly. Of the 13 bivalents, one chromosome is extremely large, which is characteristic of the chromosome complement of this genus. Several different chromosome numbers for this species have been reported previously (fide Fritsch 1972), n = 11, 11 + 1 m, 12 + 1 m, 13, 13 + 1 m, 13 + 2 m, 14, 14 + 2 m, and 24. Messmer & Lersten (1968) report n = 14 + 2 m from a population in Iowa, but judging from their figures the chromosome number consists of 13 bivalents and 2 minute accessory chromosomes. Although the number n = 14 has been published by Smith & Newton (1967), one of the bivalents as described by them is small. Additionally, Smith and Newton also observed that one large bivalent and one medium-sized bivalent usually separate precociously. Thus, there might be two chromosome races of the species in the United States, i.e. n = 13 + 1 m and n = 13 + 2 m. POTTIA TRUNCATA (Hedw.) Fiirnr. ex B.S.G., n = 26 (Fig. 2-3). Pennsylvania, Centre Co., campus of The Pennsylvania State University, ca. 400 m alt., on soil, associated with Aphanorrhegma serratum and weeds, Lin 008. This count, n = 26, is the first report for the species reported from the United States; the number is the same as that reported by Visotskaya (1967, fide Fritsch 1972) from Russia. Other counts of P. truncata are n = 25 by Vaarama (1950) from Finland and Javorcikova & Somsakova (1967, also fide Fritsch 1972) from Czechoslovakia, and n = 20 and 52 by Smith & Newton (1967) from England and Ireland. 007-2745/81/370-374$0.65/0 This content downloaded from 207.46.13.129 on Fri, 01 Jul 2016 06:00:58 UTC All use subject to http://about.jstor.org/terms 1981] LIN: CHROMOSOME NUMBERS 371