Commune Var Research Articles

<strong>New or interesting records of bryophytes from the Azores</strong>

Lepidozia stuhlmannii, L. pearsonii, Atrichum tenellum, Bryum lanatum, Campylopus subulatus, Ceratodon stenocarpus, Polytrichum commune var. humile and Thuidium delicatulum are reported as new to the Azores. The record of Sphagnum pylaisii from Terceira is referred to a monoclade expression of S. denticulatum. The presence of the North American Leucobryum albidum on the Azores is confirmed and the distinguishing characters between this species and Leucobryum juniperoideum are discussed. The recently described Thamnobryum rudolphianum is reported another time from Terceira. Campylopus brevipilus and Racomitrium aquaticum are reported as new to Pico.

Molecular Markers Reveal Cryptic Species Within Polytrichum commune (Common Hair‐Cap Moss)

Abstract: Based on morphological characters only, the taxonomy of the moss genus Polytrichum has still not been fully resolved. Application of molecular techniques might clarify some of these problems. Within P. commune s.l., the taxonomic status of several varieties, e.g., P. commune var. commune and P. commune var. uliginosum, is still debated. This study uses allozyme electrophoresis to show that there are two distinct allozyme multi‐locus genotypes within our P. commune samples. These two multi‐locus genotypes coincide with both differences in morphology and differences in habitat association. This division is corroborated by observations from different Danish and Dutch populations. Based on these results, in connection with a genetic comparison of the two infraspecific taxa of P. commune s.l. with a related species P. formosum, we argue that P. commune var. commune and P. commune var. uliginosum are two genetically distinct entities with fixed morphological differences and a considerable niche differentiation. They should, therefore, be regarded as two distinct species: P. commune and P. uliginosum.

RAPD markers for genetic differentiation of species within Polytrichum (Pofytrichaceae, Musci): a preliminary survey

SummaryZouhair, R., Corradini, P., Defontaine A. & Hallet, J. N.: RAPD markers for genetic differentiation of species within Polytrichum (Polytrichaceae, Musci): a preliminary survey – Taxon 49: 217–229. 2000. – ISSN 0040‐0262.A combination of morphological data and RAPD markers were analysed using thirty colonies from Brittany (France) in six taxa of Polytrichum: P. commune, P. c. var. perigoniale, P. formosum, P. juniperinum, P. piliferum, and P. strictum. Ten primers selected for the RAPD study produced 166 polymorphic markers useful for cluster analysis. The Jaccard index of similarity was high within and among taxa and varied from 0.56 between P. commune and P. formosum to 0.89 between P. formosum and P. juniperinum. For the morphological study, shape of terminal cells of the green lamellae covering the upper surface of leaves allowed differentiation of taxa. In P. commune var. perigoniale these cells were narrower and less deeply notched than in P. commune. The diameter of leaves was scored for many individuals of the six taxa and revealed a sexual dimorphism for size. Female plants have a significantly larger leaf rosette diameter than male plants. Morphological results are largely consistent with RAPD data. However, the high level of genetic differences of P. c. var. perigoniale and P. strictum with other taxa demonstrates the potential of molecular and genetic data in phylogenetic analysis among closely related taxa. The cluster analysis divides the taxa into two groups: (1) P. commune, P. formosum and P. c. var. perigoniale; and (2) P. juniperinum, P. piliferum, and P. strictum. The results do not support splitting the genus into Polytrichum and Polytrichastrum nor the possibility of hybrid origin of P. c. var. perigoniale between P. commune and P. formosum.

Genetic Similarities among the Hair-Cap Mosses (Polytrichaceae) as Revealed by Enzyme Electrophoresis

We used horizontal starch-gel electrophoresis to examine genetic similarities among 24 species of the Polytrichaceae. Mean genetic identity between species ranged from 0.281 to 0.998. Species of Oligotrichum and Pogonatum were genetically similar to their congeners and clearly differentiated from the other taxa. Species that have traditionally been placed in Polytrichum on the basis of their morphological characters were separated genetically into three groups. The first two groups included taxa commonly recognized in Polytrichum sect. Polytrichum and sect. Juniperifolia. The third group consisted of some, but not all, of the taxa sometimes placed in the segregate genus Polytrichastrum. A duplicated locus in all species of Polytrichum sensu stricto supports the uniqueness of this group vis-a-vis Polytrichastrum and other taxa. Polytrichastrum alpinum, the type species for the genus, was quite dissimilar genetically from other taxa commonly placed in the genus. This was also true for P. sexangulare, which showed high genetic affinity to a morphologically similar taxon commonly placed in Pogonatum. The Polytrichaceae are a relatively small family of mosses comprised of 19 genera and ca 200 species (Hyv6nen et al. 1998). Several species, such as Polytrichum commune and P. juniperinum (authorities are listed in Table 2), are familiar to many researchers due to their robust size and nearly cosmopolitan occurrence in the Northern Hemisphere. These and other species of the Polytrichaceae have been used extensively in a variety of studies. Investigations of their population biology, recently reviewed by Wyatt and Derda (1997), have contributed significantly to our understanding of several ecological and genetic phenomena in bryophytes. Historically, the taxonomy of the hair-cap mosses (subclass Polytrichidae) has been problematical at all hierarchical levels (Wyatt & Derda 1997). Most troublesome has been the placement of several species traditionally placed in Polytrichum and Pogonatum (Table 1). Many of these display morphological characters that cross the boundaries of both traditional and recently proposed genera (Merrill 1992). Several authors (e.g., Crum & 1981; Lawton 1971; Osada 1966) have followed the traditional taxonomic treatment of Frye (1937), who split Polytrichum from Pogonatum solely on the basis of terete versus angled capsules (Merrill 1992). Nevertheless, even authors who have used this simple approach have admitted that the division is unnatural and that there remain taxa that are difficult to place (e.g., P. alpinum). In a re-evaluation of generic concepts in the Polytrichaceae, Smith (1971) proposed the division of Polytrichum sensu lato into Polytrichastrum and Polytrichum sensu stricto. This was done on the basis of the pterygodont peristome, membranous and persistent epiphragm, and knife-edged, four-angled capsule in Polytrichum. In contrast, species of Polytrichastrum possess a leiodont peristome, a thick and deciduous epiphragm, and a capsule geometry that is either terete or with 4-6 rounded angles (Merrill 1992). Smith's (1971) concepts were adopted in a checklist of Fennoscandian mosses by Koponen et al. (1977), but et al. (1990) in their recent checklist of the mosses of North America chose to recognize Polytrichastrum in a new sense, including only the type speciesP. alpinum-in that genus. The problematical species under examination in this study and their generic placement by different authors (Anderson et al. 1990; Frye 1937; Koponen et al. 1977; Merrill 1992) are presented in Table 1. The treatment by Merrill (1992) as presented here differs from an earlier treatment (Smith 1971) only in the recognition of a new genus, Meiotrichum, to accommodate M. lyallii. Most evident in the table is the division of Polytrichum sensu lato, with the same taxa assigned to the segregate genera (Poly0007-2745/99/352-365$1.55/0 This content downloaded from 207.46.13.124 on Wed, 22 Jun 2016 05:26:45 UTC All use subject to http://about.jstor.org/terms 1999] DERDA ET AL.: POLYTRICHACEAE 353 TABLE 1. Four taxonomic treatments of problematic taxa of Polytrichaceae considered in this study. Polytrichum lyallii is separated from other members of the genus under Anderson et al. in order to maintain horizontal alignment of the species. NR = not recognized taxonomically; OR = outside the range of the taxon. Fry 1937 Merrill 1992 Koponen et al. 1977 et al. 1990 Polytrichum Polytrichum Polytrichum Polytrichum commune commune commune commune var. jensenii NR jensenii var. jensenii juniperinum juniperinum juniperinum juniperinum var. alpestre strictum strictum strictum piliferum piliferum piliferum piliferum var. hyperboreum hyperboreum hyperboreum hyperboreum Polytrichastrum Polytrichastrum gracile longisetum longisetum longisetum formosum formosum formosum formosum NR pallidisetum pallidisetum pallidisetum obioense obioense OR ohioense NR appalachianum OR appalachianum norvegicum sexangulare sexangulare sexangulare

Genetic Variation in the Common Hair-Cap Moss, Polytrichum commune

Levels of electrophoretically detectable genetic variation were examined at 12 enzyme loci in 21 populations of the common hair-cap moss. Mean genetic diversity within populations was comparable to other moss species (H, = 0.069 ? 0.028; mean ? standard error), but differences among populations were greater than expected for a dioecious species that regularly produces sporophytes (GST = 0.392 ? 0.078). Differentiation among populations is lower in mountainous regions than at lower elevations, possibly due to historical disturbances by man at lower elevations. Despite large overall differences among populations, mean genetic identities for P. commune were high (I = 0.933 ? 0.004), due to the widespread occurrence of several common alleles. Of 38 multilocus genotypes, 69% were distributed evenly across the range of P. commune. Mean genotypic diversity was 0.546 ? 0.042. This low value, coupled with the fact that P. commune can reproduce asexually, suggests that spore-mediated gene dispersal is limited. Furthermore, indirect estimates of the number of migrants per generation (Nm = 0.71, calculated from GST; Nm = 0.42, calculated from the frequency of rare alleles) indicate that gene flow among populations is restricted. Polytri- chum commune var. perigoniale, distinguished by some taxonomists, is not genetically distinct from var. commune.

A Checklist of the Mosses of Alaska

A Checklist of the Mosses of Alaska

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