Disjunctive Distributions Research Articles

Foordus gen. nov., a new genus of euophryine jumping spider from South Africa (Salticidae, Araneae)

A new monotypic genus Foordusgen. nov. with Foordus stefanisp. nov. as the type species is described. A short discussion on other Salticidae with disjunctive distributions is provided.

Effects of environmental factors and heavy metals on the vertical distribution of bryophytes in a sinkhole environment.

A sinkhole ecosystem, as a refuge for plant diversity, has been subjected to intensive exploitation, leading to ecosystem destruction of sinkholes in China. Understanding the responses of bryophyte distribution to destruction of the sinkhole environment are crucial to implementing protection measures for bryophyte diversity. Haolong sinkhole in Guangxi Zhuang Autonomous Region of China, the third largest sinkhole in the world, was selected as the study area. The Wilson Shmida index was used to analyse bryophyte species diversity; a Generalized Linear Model (GLM) was used to reveal species vertical distribution of bryophytes, the Single and Multiple Species Distribution Models (SSDM, MSDM) were used for analysis of the relationship between bryophyte species distribution, environmental factors and heavy metals. A total of 183 species from 74 genera in 36 families of bryophytes were collected from Haolong sinkhole, of which 26 species are endemic to China. Bryophyte species diversity was ranked in the order: agricultural section<forest section<grassland. In the vertical direction, bryophyte distribution was divided into point, disjunctive and continuous distributions using the GLM. The SSMA and MSDM indicated that bryophyte species of each of these three distributions can be divided into a temperature-slope zone, light-depth-pH-humidity zone, Pb (B)-Hg (B) zone and mixed heavy metals zone according to the effect of environmental factors and heavy metals such as As. Environmental factors or heavy metals, such as As, in Haolong sinkhole effectively cooperate in bryophyte distribution. An effective way to protect bryophyte diversity, in particular species endemic to China in the sinkhole environment, is through education and involvement of the local villagers to minimize further damage to the sinkhole environment.

New and interesting lichen records from the Ural Mountains, Russia

Ten species of lichenized ascomycetes are reported from the Urals. Aspicilia spermatomanes, Fuscidea praeruptorum, Lepra excludens, L. monogona, Metamelanea caesiella and Pertusaria amarescens are new to Russia while Bryobilimbia ahlesii, Lecanora orosthea, L. rouxii and Tephromela grumosa are new for the Urals. Our records considerably extend the ranges or fill gaps in the formerly disjunctive distributions of these species. The morphology, secondary chemistry and ecology of the species are discussed.

Time-spatial distribution of Pinus in the Korean Peninsula

Despite the ecological and landscape importance and the public popularity of conifers, especially in the case of Pinus of Pinaceae in the Korean Peninsula, not much scientific information related to vegetation is known. A wide range of fossil data has been collated and analyzed to understand the past vegetation history and current distribution and ecology, and to predict the future ranges of Pinus species in Korea in connection with climate change.Though the existing earliest Pinus (diploxylon) dates to the Cretaceous, Pinus became more common since the Miocene, and shows widespread distribution in lowland and montane areas during the Quaternary. Separation of geographical distribution of haploxylon and diploxylon Pinus since the Pleistocene may be the result of the climatic fluctuations and availability of diverse habitat. Dominance of Pinus during the Holocene may be related to both natural climatic warming as well as anthropogenic disturbance, such as, selective deforestation, agricultural activities and fire.The present occurrence of cold-tolerant Pinus pumila at northern and central alpine and subalpine belts of the Korean Peninsula indicates that the cool and hostile climate at high elevation guaranteed the survival of glacial relics in post glacial climate. The presence of Pinus koraiensis at mid elevations on mountains of northern and central Korea might be due to the cool climate in the Pleistocene.Thanks to a mild climate and seeds with wings, combined with an abundance of poor soil provided by human disturbance, Pinus densiflora became a dominant tree species at lowland and montane areas. The presence of Pinus thunbergii mainly along southern coastal regions may also be related to the local climatic condition. Disjunctive distributions of Pinus parviflora on remote islands, such as Ulleung Island and some Japanese Isles, demands further study regarding the long distance dispersal of seeds by birds, and relation to an oceanic climate. More information is needed to discuss the distributions of Pinus tabulaeformis var. mukdensis at sites in northern Korea. Special concern and protection are required for vulnerable conifer species with limited or narrow distributional ranges on high mountains and in rapidly changing environments, due climate change and environmental degradation.

High mountain origin, phylogenetics, evolution, and niche conservatism of arctic lineages in the hemiparasitic genus Pedicularis (Orobanchaceae)

The origin of the arctic flora covering the northernmost treeless areas is still poorly understood. Arctic plants may have evolved in situ or immigrated from the adjacent ecosystems. Frequently arctic species have disjunctive distributions between the Arctic and high mountain systems of the temperate zone. This pattern may result from long distance dispersal or from glacial plant migrations and extinctions of intermediate populations. The hemiparasitic genus Pedicularis is represented in the Arctic by c. 28 taxa and ranks among the six most species-rich vascular plant genera of this region. In this study, we test the hypothesis that these lineages evolved from predecessors occurring in northern temperate mountain ranges, many of which are current centers of diversity for the genus. We generated a nuclear ribosomal and chloroplast DNA phylogeny including almost all of the arctic taxa and nearly half of the genus as a whole. The arctic taxa of Pedicularis evolved 12–14 times independently and are mostly nested in lineages that otherwise occur in the high mountains of Eurasia and North America. It appears that only three arctic lineages arose from the present-day center of diversity of the genus, in the Hengduan Mountains and Himalayas. Two lineages are probably of lowland origin. Arctic taxa of Pedicularis show considerable niche conservatism with respect to soil moisture and grow predominantly in moist to wet soils. The studied characteristics of ecology, morphology, and chromosome numbers of arctic Pedicularis show a heterogeneous pattern of evolution. The directions of morphological changes among the arctic lineages show opposing trends. Arctic taxa are chiefly diploid, the few tetraploid chromosome numbers of the genus were recorded only for arctic taxa. Five arctic Pedicularis are annuals or biennials, life forms otherwise rare in the Arctic. Other genera of the Orobanchaceae consist also of an elevated number of short-lived species, thus hemiparasitism may favor this life form in the Arctic.

Early evolution and historical biogeography of fishflies (Megaloptera: Chauliodinae): implications from a phylogeny combining fossil and extant taxa.

Fishflies (Corydalidae: Chauliodinae) are one of the main groups of the basal holometabolous insect order Megaloptera, with ca. 130 species distributed worldwide. A number of genera from the Southern Hemisphere show remarkably disjunctive distributions and are considered to be the austral remnants or “living fossils” of Gondwana. Hitherto, the evolutionary history of fishflies remains largely unexplored due to limited fossil record and incomplete knowledge of phylogenetic relationships. Here we describe two significant fossil species of fishflies, namely Eochauliodes striolatus gen. et sp. nov. and Jurochauliodes ponomarenkoi Wang & Zhang, 2010 (original designation for fossil larvae only), from the Middle Jurassic of Inner Mongolia, China. These fossils represent the earliest fishfly adults. Furthermore, we reconstruct the first phylogenetic hypothesis including all fossil and extant genera worldwide. Three main clades within Chauliodinae are recognized, i.e. the Dysmicohermes clade, the Protochauliodes clade, and the Archichauliodes clade. The phylogenetic and dispersal-vicariance (DIVA) analyses suggest Pangaean origin and global distribution of fishflies before the Middle Jurassic. The generic diversification of fishflies might have happened before the initial split of Pangaea, while some Gondwanan-originated clades were likely to be affected by the sequential breakup of Pangaea. The modern fauna of Asian fishflies were probably derived from their Gondwanan ancestor but not the direct descendents of the Mesozoic genera in Asia.

Biogeographical Consequences of Cenozoic Tectonic Events within East Asian Margins: A Case Study of Hynobius Biogeography

Few studies have explored the role of Cenozoic tectonic evolution in shaping patterns and processes of extant animal distributions within East Asian margins. We select Hynobius salamanders (Amphibia: Hynobiidae) as a model to examine biogeographical consequences of Cenozoic tectonic events within East Asian margins. First, we use GenBank molecular data to reconstruct phylogenetic interrelationships of Hynobius by Bayesian and maximum likelihood analyses. Second, we estimate the divergence time using the Bayesian relaxed clock approach and infer dispersal/vicariance histories under the ‘dispersal–extinction–cladogenesis’ model. Finally, we test whether evolutionary history and biogeographical processes of Hynobius should coincide with the predictions of two major hypotheses (the ‘vicariance’/‘out of southwestern Japan’ hypothesis). The resulting phylogeny confirmed Hynobius as a monophyletic group, which could be divided into nine major clades associated with six geographical areas. Our results show that: (1) the most recent common ancestor of Hynobius was distributed in southwestern Japan and Hokkaido Island, (2) a sister taxon relationship between Hynobius retardatus and all remaining species was the results of a vicariance event between Hokkaido Island and southwestern Japan in the Middle Eocene, (3) ancestral Hynobius in southwestern Japan dispersed into the Taiwan Island, central China, ‘Korean Peninsula and northeastern China’ as well as northeastern Honshu during the Late Eocene–Late Miocene. Our findings suggest that Cenozoic tectonic evolution plays an important role in shaping disjunctive distributions of extant Hynobius within East Asian margins.

Niche partitioning and coexistence between two mammalian herbivores in the Dry Chaco of Argentina

Competitive interactions are known to be stronger between morphologically similar and phylogenetically closely related sympatric species. Patagonian mara ( Dolichotis patagonum) and Chacoan cavy ( Pediolagus salinicola) are two medium-sized herbivorous mammals which have disjunctive distributions within a sympatric region characterized by dry woodlands and shrublands (Dry Chaco, Argentina). The niche partition hypothesis predicts that ecologically similar species living together should show differentiation in at least one of the main niche dimensions to avoid competition. Thus, we predict that Patagonian mara and Chacoan cavies will differentiate in the use of trophic and/or spatial niche. To prove this hypothesis, we sampled 26 study sites in the dry and wet season and collected fresh faeces of both species. We estimated the diet composition using microhistological analysis of faeces. For habitat analysis we measured 16 vegetation variables, as well as habitat complexity and heterogeneity structure. Our results showed that during the dry season, both species segregate their diet but not their habitat niche, whereas during the wet season they segregate their habitat, and diet segregation is diffused. Diet overlap was similar between seasons, indicating a change in the foraging strategy of the cavy, which selected forbs, grasses, succulents and trees in the dry season and only grasses in the wet season. Our results support the niche partition hypothesis as a mechanism of coexistence among ecologically similar species in the South American temperate arid lands.

Phylogeny and Biogeography of Exacum (Gentianaceae): A Disjunctive Distribution in the Indian Ocean Basin Resulted from Long Distance Dispersal and Extensive Radiation

Disjunctive distributions across paleotropical regions in the Indian Ocean Basin (IOB) often invoke dispersal/vicariance debates. Exacum (Gentianaceae, tribe Exaceae) species are spread around the IOB, in Africa, Madagascar, Socotra, the Arabian peninsula, Sri Lanka, India, the Himalayas, mainland Southeast Asia including southern China and Malaysia, and northern Australia. The distribution of this genus was suggested to be a typical example of vicariance resulting from the breakup of the Gondwanan supercontinent. The molecular phylogeny of Exacum is in principle congruent with morphological conclusions and shows a pattern that resembles a vicariance scenario with rapid divergence among lineages, but our molecular dating analysis demonstrates that the radiation is too recent to be associated with the Gondwanan continental breakup. We used our dating analysis to test the results of DIVA and found that the program predicted impossible vicariance events. Ancestral area reconstruction suggests that Exacum originated in Madagascar, and divergence dating suggests its origin was not before the Eocene. The Madagascan progenitor, the most recent common ancestor of Exacum, colonized Sri Lanka and southern India via long-distance dispersals. This colonizer underwent an extensive range expansion and spread to Socotra-Arabia, northern India, and mainland Southeast Asia in the northern IOB when it was warm and humid in these regions. This widespread common ancestor retreated subsequently from most parts of these regions and survived in isolation in Socotra-Arabia, southern India-Sri Lanka, and perhaps mainland Southeast Asia, possibly as a consequence of drastic climatic changes, particularly the spreading drought during the Neogene. Secondary diversification from these surviving centers and Madagascar resulted in the extant main lineages of the genus. The vicariance-like pattern shown by the phylogeny appears to have resulted from long-distance dispersals followed by extensive range expansion and subsequent fragmentation. The extant African species E. oldenlandioides is confirmed to be recently dispersed from Madagascar.

New Localities of Some Paulia Species (Lichinaceae, Lichenized Ascomycota) from Socotra (Indian Ocean)

New localities are reported for Paulia aldabrensis, P. myriocarpa, P. perforata, and P. schroederi, all being new to the lichen flora of Socotra (Yemen, Indian Ocean). The lichens have been found in shaded sites mainly on steep limestone rock surfaces. The new records of Paulia species from Socotra are included in a discussion of distributional patterns in the genus. From the isolated and disjunctive distributions it is concluded that the Paulia species are palaeoendemics in arid to semi-arid tropical habitats with their origin on the Gondwana continent or even earlier on the pre-Gondwana center of Pangaea. The species of the genus Paulia are described as lichens occurring on limestone in dry habitats and being distributed mainly on tropical islands (Henssen 1986). However, recently a Paulia species was reported from a granite inselberg in the Ivory Coast, West Africa, along a rainwater track (Btidel et al. 1997). Two representatives of the genus, Paulia gibbosa and P. myriocarpa, were found on a granite inselberg in the Orinoco Lowland, Venezuela, (Biidel & Schultz, unpubl. records) and Paulia aldabrensis occurred in northeastern Queensland, Australia, on sandstone (Biidel & Lumbsch, unpubl. records). Paulia species are not restricted to limestone habitats and additional records from silicous rocks can be expected. In general, the 12 species that are included in the genus show quite disjunctive distributions (see Henssen 1980, 1986; Henssen & Jorgensen 1990; Henssen & Tretiach 1995; Tretiach & Henssen 1996). A synopsis of the genus is given in Table 1. This study reports on four Paulia species that have been collected on the tropical island of Socotra in the western Indian Ocean. All species are new entries to the lichen flora of the island (Mies 1994). Paulia perforata (Pers.) Asah. was known from two localities: Rawak Island (West New Guinea) and the Mariana Islands (north of New Guinea), both collections made in the early 19th century. Asahina (1958) clarified the nomenclatural situation concerning the lichen taxa Gyrophora perforata Pers. and Paulia pullata F6e and used the new name, Paulia perforata (Pers.) Asah. Paulia aldabrensis was described by Henssen (1980) from the Aldabra Islands north of Madagascar. To date the species is only known from its type locality and from Australia (see above). Paulia myriocarpa was found in Mexico, the Bermuda Islands, Puerto Rico, and Brazil (in Henssen 1986 as P. tessellata; Henssen & Tretiach 1995) and Venezuela (see above). The identities of Thyrea myriocarpa Zahlbr. and Paulia tessellata Henss. was shown by Henssen and Jorgensen (1990), with the authors consequently suggesting the new combination Paulia myriocarpa (Zahlbr.) Henss. The fourth Paulia species that has been collected on Socotra is P. schroederi, a lichen described as Thyrea schroederi by Zahlbruckner (1921) from coastal limestone rocks in Kenya (near Mombasa). Henssen and Jorgensen (1990) showed that this lichen belongs to Paulia, and suggested the name P. schroederi (Zahlbr.) Henss. It much resembles Paulia gibbosa that is to date only known from the Bermuda Islands (Henssen 1986) and Venezuela (see above). Henssen (1986) considered Paulia aldabrensis and P. perforata as belonging to an eastern group of related species on account of their distributions and the hymenial reactions with iodine. Paulia myriocarpa is thought to belong to a western group (Henssen & Tretiach 1995). Paulia schroederi is closely related to P. gibbosa of the western group and differs from that species mainly in the color of the apothecial disc and its geographic distribution (Henssen & Tretiach 1995). Our newly discovered 0007-2745/99/61-66$0.75/0 This content downloaded from 157.55.39.208 on Fri, 14 Oct 2016 04:07:22 UTC All use subject to http://about.jstor.org/terms 62 THE BRYOLOGIST [VOL. 102 TABLE 1. Characters in Paulia based on data given by Henssen (1986), Henssen and Tretiach (1995); additions in Tretiach and Henssen (1996); including our own measurements. Paulia pyrenoides (Nyl.) Henss. is excluded here since it was only tentatively placed into the genus by Henssen and co-workers (Henssen and Jorgensen 1990; Henssen and Tretiach 1995). Distribution areas: Aldabra Isl.-1, Australia-2, Bermuda-3, Brazil-4, Cuba-5, Europe-6, Jamaica-7, Japan-8, Kenya-9, Mariana Isl.-10, Mexico-11, Puerto Rico-12, Rawak-13, Socotra-14, Venezuela-15.

Didymodon anserinocapitatus (Musci, Pottiaceae) New to the New World

The moss Didymodon anserinocapitatus, previously known only from eastern China, is reported from the foothills of the Rocky Mountains in Colorado and New Mexico. Study of the genus Didymodon Hedw. in North America uncovered a distinctive species new to the flora: DIDYMODON ANSERINOCAPITATUS (X.-j. Li) Zand., Bull. Buffalo Soc. Nat. Sci. 32: 162. 1993. Barbula anserinocapitata X.-j. Li, Acta Bot. Yunnan. 3: 103. 1981. Plants green to reddish green. Stems to 1.5 cm long, central strand present, strong, sclerodermis distinct, hyalodermis absent, axillary hairs 3-4 cells long, the basal-most thicker-walled. Stem leaves erect-appressed when dry, spreading when moist, monomorphic, lanceolate, adaxially weakly concave across leaf, 0.7-1.1 mm long without tip, to 2.2 mm long whole, base short-sheathing to long-ovate or scarcely differentiated in shape, margins recurved at midleaf, entire, apex abruptly thickened, long-elliptic to ovate, of many thickwalled cells, usually soon deciduous, absent in mature leaves; costa excurrent, little widened or tapering at midleaf but swollen in excurrency, adaxial costal cells quadrate, 4-6 cells wide at midleaf, epidermis present on both sides, guide cells in 2 layers, dorsal stereid band weak, ventral absent or weak, hydroid strand sometimes present; basal laminal cells differentiated medially, walls thin; upper laminal cells 8-10 pIm wide, 1:1, papillae essentially absent, lumens angular, walls thin, weakly convex on both sides, unistratose except in deciduous apex; basal cells quadrate to rectangular. Sexual features and sporophyte unknown. Upper lamina KOH color reaction reddish orange. Didymodon anserinocapitatus is here reported for the New World from two sites in the foothills of the Rocky Mountains on the eastern edge of the Colorado Plateau. COLORADO. Fremont Co., 4.5 km up lower portion of Phantom Canyon, tributary of lower Arkansas River between Pueblo and Canyon City, red sandstone cliffs, 1,500-2,200 m elev., Weber, Hermann & Feddema B-37528, 1 June 1971 (COLO) and NEW MEXICO: San Miguel Co., Pecos, along Pecos River, (no substrate given), 2,100 m elev., Richards & Drouet 456, 21 Oct. 1939 (DUKE). This species is known otherwise only from the type locality in Tibet. The arctic-northern montane species Didymodon johansenii (Williams) Crum is similar in the swollen, deciduous apex, but differs mainly by its larger upper laminal cells (13-15 pm wide), and guide cells in only a single layer. Didymodon rigidulus var. icmadophilus (C. Mtill.) Zand., a wide-spread montane-grassland species, is similar in appearance but its leaf apices are never swollen (though sometimes fragile). Didymodon rigidulus var. subulatus (Th6r. & Bartr.) Zand. of Arizona and Mexico has bito tri-stratose, longcylindric, very fragile leaf apices, but the apices mostly taper (rarely being barely widened). Through the plane margins of the leaves and the somewhat knotted apex, the latter variety is most closely related to D. rigidulus var. icmadophilus. The Colorado and New Mexican specimens cited above are similar in size and most other respects to material from China (TIBET, Nan Xian, Zang Mu 1704, isotype-NY), but differ in the propagulum usually widest in the middle while that of the Tibetan material is usually widest below the middle and is often slightly larger. In the key to taxa of Pottiaceae with propaguliferous apices (Zander 1978), D. anserinocapitatus would key to D. johansenii. Didymodon anserinocapitatus is very closely related to D. johansenii and D. sinuosus (Mitt.) Delogn. according to a cladistic study (Zander, in prep.). Didymodon anserinocapitatus shares a similar disjunct distribution pattern with many mosses and some lichens. This pattern reflects a relationship between the floras of the Colorado Plateau and central Asia. Mosses with central or central-western North America and central Asia disjunctive distributions (most with outliers elsewhere) include Anacolia laevisphaera (Tayl.) Flow., A. menziesii (Turn.) Par., Grimmia elatior Bals. & De Not., Jaffueliobryum raui (Aust.) Th6r., J. wrightii (Sull.) Th6r., Leptodon smithii (Hedw.) Web. & Mohr, Leptop0007-2745/97/237-238$0.35/0 This content downloaded from 157.55.39.52 on Tue, 12 Jul 2016 06:17:39 UTC All use subject to http://about.jstor.org/terms 238 THE BRYOLOGIST [VOL. 100

Morphological Uniformity Among Widely Disjunct Populations of the Rare "Copper Moss," Scopelophila cataractae (Pottiaceae)

Eight morphological characters of the gametophyte generation and three of the sporophyte generation were measured in 15 plants from each of 76 populations of the rare and geographically disjunctive moss, Scopelophila cataractae, in order to assess whether subtle differences exist between plants from widely separated populations. Plants were variable in all morphological traits, but most of the variation occurred among individual stems within populations and among populations within broad geographic regions. In spite of statistically significant differences between plants from widely disjunct regions (including different continents) for eight of the 11 morphological traits, the percentage of the total variation attributable to regional differences was minimal. Little regional variation in individual traits was corroborated by multivariate analyses including UPGMA clustering and principal component analysis. Furthermore, the degree and pattern of correlations among morphological traits were remarkably similar in populations of plants separated by thousands of miles. The general rarity and habitat specificity of S. cataractae throughout its range suggest that widely disjunct populations have been continuously separated. This, combined with the present analysis of morphology, suggests that morphological diversification may occur slowly in this moss. Relative to seed plants, most species of have broad geographic ranges. Less than 25% of the of the eastern United States, for example, are endemic even in the broad regional sense, with most taxa occupying remarkably broad ranges that include Europe and/ or Asia (Crum and Anderson 1981; Schuster 1983). Even in floristically rich areas such as the Ozarks, 90% of the are widespread elsewhere in the eastern United States and 70% occur also in the Old World (Crum and Anderson 1981). Indeed, on a worldwide basis, endemism at the specific level is low in mosses. It is common knowledge among moss monographers that many species occur disjunctively on several continents and that there is often little or no morphological differentiation between widely disjunct populations. These systematic and biogeographic observations have led some bryologists to hypothesize that many species of are geologically old and that presently disjunct populations of such species have undergone little or no morphological evolution over vast amounts of time (Crum 1972; Crum and Anderson 1981; Schuster 1983). Arguments in this regard often cite the observation that many intraspecific disjunctions in correspond to the same patterns that occur at the generic level in seed plants. Such patterns (e.g., eastern Asia-eastern North America) have been widely accepted as having derived from fragmentation of the Arctotertiary flora (Herzog 1926; Crum 1972). The likelihood of more recent long-range dispersal has also been discussed for some species (e.g., van Zanten 1984; van Zanten and Pocs 1981). In spite of the common perception of monographers that little morphological differentiation exists between widely disjunct populations of many mosses, there have been few quantitative studies to determine whether subtle patterns of regional variation do in fact occur. The ecologically unique mosses provide an especially good opportunity to address this issue. The copper include about ten species of and liverworts that exhibit an ecological association with substrates with higher than average concentrations of copper or other metals (Persson 1948, 1956; Shacklette 1967). In addition to the unusual habitat of the copper mosses, these species share the characteristic of having remarkably broad and highly disjunctive geographic distributions. Furthermore, most of the copper do not reproduce sexually (as evidenced by sporophyte formation) over large portions of their ranges. One such copper moss, Scopelophila cataractae (Mitt.) Broth., occurs disjunctively in central America and Mexico, the United States, Europe, the Himalayan Mountains, and southeast Asia including the Philippine Islands northward to Japan (Zander 1967). The species is extremely rare throughout its range. In the United States, for example, it occurs at one locality each in

Ecology and phytogeographical affinities of the bryophytes in the Inner Hebrides

SynopsisOf just under 1000 species of bryophyte known in the British Isles, 597 are recorded in the Inner Hebrides. This diversity of species is due to several factors: the suitability of the climate for bryophyte growth, the rich variety of bryophyte habitats and the presence of several phytogeographical elements in the islands.Bryophyte species occur in varying numbers in almost all habitats from the spray zone at high water mark to the tops of mountains. Compared with the Outer Hebrides and the adjacent mainland, certain bryophytes are absent from the islands. This is largely due to the scarcity of dune slacks in the Inner Hebrides, and the poorer development of high mountain habitats.Examples are given of a number of typical Inner Hebridean habitats together with their characteristic bryophyte species.Naturally the Inner Hebrides are rich in species with an oceanic distribution in the British Isles. These are analysed into groups based on their world distributions. A number of species with strongly disjunctive distributions are thought to be Tertiary relicts in the British flora.A list of the bryophytes recorded in the Inner Hebrides is appended giving presence or absence in each island or group of islands.