Native North American Plant Research Articles

Characterization of Odorants in Clustered Mountain Mint Pycnanthemum muticum.

The clustered mountain mint, Pycnanthemum muticum, is a pleasant-smelling, native North American plant. Despite its wide geographical presence across the United States and Canada, little is known about the specific odorants responsible for its pleasing aroma. Herein, 42 odorants were identified in the plant through solvent-assisted flavor evaporation (SAFE), gas chromatography-olfactometry (GC-O), and gas chromatography-mass spectrometry (GC-MS). Subsequent analysis involved determining flavor dilution (FD) factors using aroma extract dilution analysis (AEDA), quantitating 14 odorants through stable isotope dilution assays (SIDA), and calculating their odor activity values (OAVs). Several noteworthy odorants with OAV ≥ 1 included pulegone (mint, medicinal; OAV 276), 1-octen-3-one (mushroom; OAV 149), menthofuran (mint, petrol; OAV 139), nonanal (citrus; OAV 21), γ-nonalactone (coconut; OAV 13), 1,8-cineole (eucalyptus; OAV 12), mintlactone (mint, coconut; OAV 12), menthone (mint, fresh; OAV 7.3), α-pinene (pine; OAV 4), and piperitenone (mint; OAV 1.9). The study also determined the stereochemistry of various chiral odorants. An aroma simulation model was developed to validate the identification and quantitative results; upon evaluation using olfactory profile analysis, no significant differences were found between the aroma model and an aqueous infusion of P. muticum (P > 0.05). These findings lay the foundation for future investigations into the diversity of P. muticum selections and can provide valuable insights for studies on plant hybridization for food and flavor applications.

Pesticide Contamination in Native North American Crops, Part I-Development of a Baseline and Comparison of Honey Bee Exposure to Residues in Lowbush Blueberry and Cranberry.

A pesticide exposure baseline for honey bees was compiled for two New England cropping systems, the native North American plant species consisting of lowbush blueberry (Vaccinium angustifolium Aiton) and cranberry (Vaccinium macrocarpon Aiton). More unique pesticide compounds were applied in blueberry than cranberry, but the numbers of pesticides discovered in trapped honey bee pollen were similar between the two crop systems. Not all pesticides found in pollen were the result of the applications reported by growers of either crop. When comparing residues, number of pesticides detected, total concentration, and risk quotient varied between the two crops. Also, blueberry was dominated by fungicides and miticides (varroacides) and cranberry was dominated by insecticides and herbicides. When comparing reported grower applications that were matched with detection in residues, the proportion of pesticide numbers, concentrations, and risk quotients varied by crop system and pesticide class. In most cases, pesticide residue concentrations were of low risk (low risk quotient) to honey bees in these crops. Estimation of decay rates of some of the most common pesticide residues under field conditions could aid growers in selection of less persistent compounds, together with safe application dates, prior to bringing in honey bees for pollination.

Additional host range testing of Eucryptorrhynchus brandti (Coleoptera: Curculionidae) for the biological control of tree-of-heaven, Ailanthus altissima (Simaroubaceae) in the U.S.A.

ABSTRACT Ailanthus altissima, native to China, is a highly invasive plant in North America, Europe, and other continents. This species displaces native plants by forming dense clonal thickets. Ailanthus altissima is shade intolerant, quickly invades fields, rights-of-way, urban areas, and areas in forests disturbed by logging, fire, or pests. This species is also a primary host of the economically damaging spotted lanternfly, Lycorma delicatula, recently introduced into the U.S. Eucryptorrhynchus brandti is native to China and has been identified as a potential biological control agent of A. altissima. Oviposition studies conducted on 11 non-target plant species demonstrated that E. brandti oviposited only on the U.S. native Leitneria floridana. All non- Leitneria species had adult feeding of less than 2% compared to A. altissima, with no oviposition or larval development. Longevity of E. brandti in no-choice tests with L. floridana and L. pilosa subsp. ozarkana, was shorter and the weevils consumed less foliage compared to A. altissima. Seventeen percent of the L. floridana trees tested had larval feeding and 18 E. brandti adults emerged from 10 replicates. No L. floridana trees with larval feeding died. All the A. altissima trees with larval development died. Eucryptorrhynchus brandti is projected to be an effective agent against A. altissima and pose no significant risk to native North American plant species, with potential to be an additional management tool for the spotted lanternfly.

Genomic Sequence of Canadian Chenopodium berlandieri: A North American Wild Relative of Quinoa.

Chenopodium berlandieri (pitseed goosefoot) is a widespread native North American plant, which was cultivated and consumed by indigenous peoples prior to the arrival of European colonists. Chenopodium berlandieri is closely related to, and freely hybridizes with the domesticated South American food crop C. quinoa. As such it is a potential source of wild germplasm for breeding with C. quinoa, for improved quinoa production in North America. The C. berlandieri genome sequence could also be a useful source of information for improving quinoa adaptation. To this end, we first optimized barcode markers in two chloroplast genes, rbcL and matK. Together these markers can distinguish C. berlandieri from the morphologically similar Eurasian invasive C. album (lamb's quarters). Second, we performed whole genome sequencing and preliminary assembly of a C. berlandieri accession collected in Manitoba, Canada. Our assembly, while fragmented, is consistent with the expected allotetraploid structure containing diploid Chenopodium sub-genomes A and B. The genome of our accession is highly homozygous, with only one variant site per 3-4000 bases in non-repetitive sequences. This is consistent with predominant self-fertilization. As previously reported for the genome of a partly domesticated Mexican accession of C. berlandieri, our genome assembly is similar to that of C. quinoa. Somewhat unexpectedly, the genome of our accession had almost as many variant sites when compared to the Mexican C. berlandieri, as compared to C. quinoa. Despite the overall similarity of our genome sequence to that of C. quinoa, there are differences in genes known to be involved in the domestication or genetics of other food crops. In one example, our genome assembly appears to lack one functional copy of the SOS1 (salt overly sensitive 1) gene. SOS1 is involved in soil salinity tolerance, and by extension may be relevant to the adaptation of C. berlandieri to the wet climate of the Canadian region where it was collected. Our genome assembly will be a useful tool for the improved cultivation of quinoa in North America.

Distribution of Prunus serotina Ehrh. in North America and Its Invasion in Europe

Black cherry (Prunus serotina Ehrh.) is a native North American plant species. It includes five subspecies and is currently invasive in Europe. Since pre-Hispanic times, black cherry has been known and used by American inhabitants, and its botanical use was reported in the 19th century. The present study describes the taxonomic richness and taxonomic diversity of the species based on data from 554 taxonomically confirmed collection sites. Additionally, 19 climatic parameters were used to estimate the current and future potential distribution patterns of black cherry applying a climate change model to North America and Europe. Regions of northeast Mexico, northwestern Mexico, the Great American Basin, and the Mississippi River-Great Lakes region in the USA are shown as areas where taxa of P. serotina are present. The potential distribution model of black cherry in North America shows a continuous pattern starting in the Center of Mexico and following both main Mexican mountain ranges (Sierra Madre Oriental and Sierra Madre Occidental). The pattern extends following two different paths throughout northern Mexico toward the Rocky Mountains and the Appalachians in the USA. Based on the NOAA-CCM3 climatic change model, decreased rainfall in wetlands will result in changes in future patterns in America. When applied to Europe, our model shows more extensive regions and more accurately than previous estimations; thus, the current potential distribution of the species includes important areas in the western part of the continent. The potential effect of climate change on P. serotina distribution suggests new and wider areas of possible invasion of this species throughout the continent mainly in France, Germany, and Italy. We suggest take into account the whole American taxa included in this species in the end to study its potential invasion in Europe and establishing suitable control strategies.

1H-NMR Guided Isolation Of Acetogenins From Asimina Triloba

Asimina triloba Dunal is a native North American plant commonly named the paw tree. The acetogenins existing in the Asimina triloba are a well-established class of compounds with significant anti-tumor bioactivities [1]. In order to obtain the acetogenins, a methanol extract of A. triloba was fractionated repeatedly over reversed phase (C-18) and normal phase silica gel. The 1H-NMR spectra of fractions were recorded to select the acetogenin enriched fractions by examining the characteristic resonances at about δ 7, 5, 3.6 – 3.9, and 1.2 – 1.4 [2]. Many acetogenins were isolated from the selected fractions and their structures were elucidated based on 1D- and 2D-NMR and HRESIMS data analyses.

Native plants provide equal or better nutrition than crop plants in wildlife plantings

As a wildlife biologist, I have often wondered about the tendency of land managers toward planting nonnative species for wildlife, purportedly because of superior nutritional characteristics. Therefore, I analyzed seeds of 26 species of plants for 3 key nutritional factors: gross energy, crude protein, and crude fat. Six of the species were nonnative (including 4 common agricultural crops), whereas the other 20 were native North American plants often reported in wildlife food habits studies. Two crop plants ( Helianthus annuus L. [Asteraceae] and Glycine max (L.) Merr. [Fabaceae]), one nonnative plant ( Lespedeza bicolor Turcz. [Fabaceae]), and 7 native species had the 10 highest values of crude fat. Glycine max , along with 2 nonnative Lespedeza species and 7 native species had the greatest values of crude protein. For gross energy, Helianthus annuus and Glycine max , along with 8 native species, ranked highest. When comparing the combination of gross energy, crude fat, and crude protein for all species, 4 nonnative and 6 native species ranked highest. This study, the first to test these species with identical procedures, provides comparative evidence that supports using native plants, rather than agricultural and other nonnative species, to supply wildlife winter food.

Inured to Empire: Wild Rice and Climate Change

Wild rice might have become the consummate alternative foodstuff of the British Empire. This edible native North American plant was the subject of significant, if subsequently forgotten, investigation between the Seven Years’ War and the Napoleonic Wars. During this period of ongoing military conflict, imperial expansion, and subsistence crises, colonists, naturalists, and officials also grappled with the possibility that climates were undergoing continuous, perhaps permanent, transformation. They envisioned wild rice as the pioneer plant of a responsive imperial ecology, uniquely suited to weathering all political seasons and untold natural upheavals. Neglecting Native American horticultural practice, they wrote about exploiting wild rice on a larger scale as the realization of a biblical and imperial dream of guaranteed abundance: a self-reproducing, prodigious staple impervious to unexpected developments, including “inexplicable” changes in the climate.

Reciprocal interactions between native and introduced populations of common milkweed, Asclepias syriaca, and the specialist aphid, Aphis nerii

Following its introduction into Europe (EU), the common milkweed (Asclepias syriaca) has been free of most specialist herbivores that are present in its native North American (NA) range, except for the oleander aphid Aphis nerii. We compared EU and NA populations of A. nerii on EU and NA milkweed populations to test the hypothesis that plant–insect interactions differ on the two continents. First, we tested if herbivore performance is higher on EU plants than on NA plants, because the former have escaped most of their herbivores and have perhaps been selected for lower defence levels following introduction. Second, we compared two A. nerii lines (one from each continent) to test whether genotypic differences in the herbivore may influence species interactions in plant–herbivore communities in the context of species introductions. The NA population of A. nerii developed faster, had higher fecundity and attained higher population growth rates than the EU population. There was no overall significant continental difference in aphid resistance between the plants. However, milkweed plants from EU supported higher population growth rates and faster development of the NA line of A. nerii than plants from NA. In contrast, EU aphids showed similar (low) performance across plant populations from both continents. In a second experiment, we examined how chewing herbivores indirectly mediate interactions between milkweeds and aphids, and induced A. syriaca plants from each continent by monarch caterpillars (Danaus plexippus) to compare the resulting changes in plant quality on EU aphid performance. As specialist chewing herbivores of A. syriaca are only present in NA, we expected that plants from the two continents may affect aphid growth in different ways when they are challenged by a specialist chewing herbivore. Caterpillar induction decreased aphid developmental times on NA plants, but not on EU plants, whereas fecundity and population growth rates were unaffected by induction on both plant populations. The results show that genetic variation in the plants as well as in the herbivores can determine the outcome of plant–herbivore interactions.

Conyza canadensis suppresses plant diversity in its nonnative ranges but not at home: a transcontinental comparison

The impact of invasive species across their native and nonnative ranges is poorly quantified and this impedes a complete understanding of biological invasions. We compared the impact of the native North American plant, Conyza canadensis, which is invasive to Eurasia, on species richness at home and in a number of introduced regions through well replicated transcontinental field studies, glasshouse experiments and individual-based models. Our results demonstrated mostly negative relationships between C. canadensis abundance and native species richness in nonnative ranges, but either positive or no relationships in its native North American range. In glasshouse experiments, the total biomass of Conyza was suppressed more by species from its native range than by species from regions where it is nonnative, but the effects of Conyza on other species did not show a consistent biogeographical pattern. Finally, individual-based models led to the exclusion of Conyza from North American scenarios but to high abundances in scenarios with species from the nonnative ranges of Conyza. We illustrate biogeographical differences in the impact of an invader across regional scales and suggest that inherent differences in one specific aspect of competitive ability, tolerance to the effects of other species, may play some role in these differences.

In Vitro Evaluation of Flavonoids from Eriodictyon californicum for Antagonist Activity against the Bitterness Receptor hTAS2R31

The leaves of the native North American plant, Eriodictyon californicum, were once used to mask the bitter taste of pharmaceuticals, an application currently of importance. Ten flavonoids (1-10) were isolated from the leaves of E. californicum, of which the structure and absolute configuration of 6-methoxyhesperetin (8) were assigned for the first time. In addition, the absolute configurations at C-2 were established for 4'-isobutyrylhomoeriodictyol (3) and 6-methoxyhomoeriodictyol (7). Using a cell-based assay, it was determined that the 7-methoxylated flavanones, sakuranetin (2) and 6-methoxysakuranetin (9), and the flavone, jaceosidin (10), are antagonists of hTAS2R31.

Abstract B69: Potential cancer chemopreventive compounds from Oplopanax horridus, a native North American plant

Abstract Distributed throughout the west of North America, the plant Oplopanax horridus, or devil's club, belongs to the genus Oplopanax, which consists of three species (O. elatus, O. japonicus and O. horridus). Although many studies on the other two species have been performed, phytochemical and pharmacological investigations on O. horridus have been limited, especially cancer chemopreventive studies. After comparing differences of antiproliferative potentials among different plant parts of O. horridus, the root bark was selected to perform further phytochemical isolation to prepare active anticancer fractionations and compounds. The hydrophobic fractions showed potent antiproliferative effects on human HCT-116 and SW-480 colorectal cancer cells. Subsequent isolation of the hydrophobic fractions gave six polyynes and one polyene; in which two novel compounds, Oplopantriol A and Oplopantriol B, were obtained and their absolute structures were elucidated by detailed spectroscopic analyses, including 1D and 2D NMR techniques and chemical methods. The content of these seven compounds in the O. horridus root bark was determined using an on-line SPE-HPLC method. Pharmacological studies showed that two polyynes, including a novel compound (Oplopantriol A), possessed strong cancer cell inhibitory activities (P < 0.001). The IC50 of these two polyynes were observed at 1-5 µM on the colorectal cancer cells. Treatment with active fraction and compounds noticeably induced apoptosis, and distinctly induced the G2/M phase arrest of the cell cycle in a time- and concentration-dependent manner. The trend of increasing cyclin A and cyclin B1 were similar to the increase of G2/M phase cells in all treated groups. These results suggested that active O. horridus fraction and selected polyynes had potential antiproliferative activities on human colorectal cancer cells. The observed cancer chemopreventive effects could be related to the induction of apoptosis and regulation of cell cycle transition. (This work was supported in part by the NIH/NCCAM grants AT003255, AT004418 and AT005362). Citation Information: Cancer Prev Res 2010;3(12 Suppl):B69.

Cytotoxicity of Atriplex confertifolia.

The search for cancer treatment continues to be a global effort. As part of this global effort, many natural products have been tested against cancer cell lines, mostly from tropically located plants. This study reports that extracts of Atriplex confertifolia (Torr. and Frem.) S. Watson (Chenopodiaceae), a native North American plant (also known as shadscale or saltbush), has significant bioactivity against human breast cancer cell lines MCF-7, MDA-MB 435, MDA-MB 231, and HeLa cells (cervical cancer cells). The bioactivity of A. confertifolia extracts on these cells lines was compared to an FDA-approved cancer drug (Onxol®) and an industry-standard leukocyte control cell line. Active portions of the extracts were found primarily in the polar fractions of the plant. A dose-response curve of the extracts displayed significant cell death similar to Onxol®. The plant extracts did not significantly inhibit the viability of the leukocyte cell line. In a timed study, over 90% of cell lines MDA-MB 435 and HeLa died after 24 hours. Cell death appears to result from apoptosis.

Physiological host range of Ceratapion basicorne, a prospective biological control agent of Centaurea solstitialis (Asteraceae)

Ceratapion basicorne (Coleoptera: Apionidae) is a weevil native to Europe and western Asia that is being evaluated as a prospective classical biological control agent of Centaurea solstitialis (yellow starthistle) in the United States. Host plant specificity of the insect was evaluated in no-choice oviposition experiments. Feeding on leaf tissue by adult females was highly correlated to oviposition rate, both of which occurred primarily on plants in the tribe Cardueae, and especially those in the monophyletic subtribe Centaureinae. The highest rates of larval development occurred on Ce. solstitialis and Centaurea cyanus (bachelor’s button, garden cornflower), and there was significant development on Centaurea melitensis (Napa starthistle, tocalote), Cnicus benedictus (blessed thistle), Carthamus tinctorius (safflower), and Crupina vulgaris (common crupina). All the plants that supported some larval development are within a monophyletic clade within the Centaureinae. No native North American plants appear to be at risk of significant damage by this insect. Additional testing of safflower and bachelor’s button under choice conditions should complement these results to help determine the degree to which these plants are at risk.

Host plant specificity and potential impact of Aceria salsolae (Acari: Eriophyidae), an agent proposed for biological control of Russian thistle (Salsola tragus)

Russian thistle (common tumbleweed), Salsola tragus (Chenopodiaceae), is an alien weed that is widespread in the western United States. A population of the eriophyid mite, Aceria salsolae (Acari: Eriophyidae), was collected in Greece and evaluated for host plant specificity as a prospective biological control agent. The mite usually does not form galls, but is a vagrant that usually inhabits the crevices of leaf and flower buds. Feeding damage causes meristematic tissue to die, which stunts the plant. The mite was able to multiply only on species in the Salsola section Kali subsection Kali, which includes the alien weeds Salsola collina, Salsola kali, and Salsola paulsenii. It did not damage or multiply on Salsola soda, which is in a different section, nor on Halogeton glomeratus, which is in the same tribe. The mite reduced the size of Russian thistle plants by 66% at 25 weeks post-infestation under artificial conditions. The results indicate that the mite poses negligible risk to nontarget native North American plants or economic plants, and it may substantially reduce the size of Russian thistle plants and their population density.

Paradoxical host shift by Depressaria pastinacella in North America: is enemy‐free space involved?

Herbivorous insects often preferentially oviposit and develop on hostplants that support suboptimal growth relative to alternative hostplants available in the same habitat. In some cases, this preference results from reduced predation risk on the nutritionally suboptimal hostplant. Thus, the availability of enemy‐free space has been postulated to affect hostplant choice for herbivorous insects. In the midwestern United States, populations of the parsnip webworm, Depressaria pastinacella Duponchel, introduced from Europe over 150 years ago, feed not only on wild parsnip, Pastinaca sativa L., one of its hosts in Europe, but also on cow parsnip, Heracleum lanatum Michx., a native North American plant. Survival of larvae in the laboratory on fruits of H. lanatum, however, is lower than on fruits of P. sativa, suggesting nutritional or chemical unsuitability. In view of the persistent use of this novel hostplant, we compared susceptibility to predation on these two hostplants in the field. Over a four‐year period, contrary to expectations, webworms pupating in cow parsnip stems consistently experienced intense predation, whereas pupae in parsnip stems escaped predation. The pattern persisted when stems of both hostplants containing pupae were placed in pots at a single location. The predator appears to be avian, as only exclosures that prevented access by both birds and mice eliminated predation, whereas exclosures preventing access by mice alone did not reduce predation. The apparent existence of enemy‐free space in wild parsnip may be due to differences in stem characteristics; parsnip stems contain significantly greater amounts of the highly photoactive furanocoumarin xanthotoxin and are also significantly tougher compared to stems of cow parsnip. The persistent use of cow parsnips by parsnip webworms in the face of high levels of predation and without clear benefits in terms of growth and development suggests that webworms may have lost genetic variation for host discrimination as a consequence of introduction.

Host Specificity of Mogulones cruciger (Coleoptera: Curculionidae), a Biocontrol Agent for Houndstongue ( Cynoglossum officinale ), with Emphasis on Testing of Native North American Boraginaceae

Recent concerns over the safety of native North American plant species in the family Boraginaceae, especially those of endangered status in the USA, prompted additional host specificity testing of the European root weevil Mogulones cruciger , a proposed agent for the biocontrol of houndstongue in the USA. M. cruciger can complete full development on species within closely-related genera in the Boraginaceae, but prefers houndstongue as a host. Of the 22 species of native North American Boraginaceae that were tested in this study, nine species from four genera within the tribe Eritrichieae ( Cryptantha, Hackelia, Mertensia and Lappula ) clearly supported development of M. cruciger . However, generally these non-target species experienced less attack by M. cruciger relative to houndstongue. There were differences in the incidence and degree of attack depending on the test type, which included the use of potted test plants in laboratory no-choice and open-field choice situations. The least non-target attack occurred on rangeland in British Columbia, Canada, where potted test plants were introduced into sites where the insect had been previously released on houndstongue. These results suggest that M. cruciger has a narrow ecological host range. Special emphasis was placed on testing species of Cryptantha because C. crassipes is listed as endangered in the USA. Six of 12 Cryptantha species tested supported full development, but generally, the incidence and intensity of attack were less for these species relative to houndstongue. There was no, or incomplete development, on tested species of Plagiobothrys , a genus that contains two species listed as endangered in the USA.

Host Specificity of Longitarsus quadriguttatus Pont., a Below-Ground Herbivore for the Biological Control of Houndstongue

Abstract Cynoglossum officinale is a Eurasian plant that has become an invasive weed of rangelands in the United States and Canada. It is a herbaceous, monocarpic, short-lived perennial. Since there are no satisfactory means of control of houndstongue, a biological control project was initiated in 1988. The first species introduced for the control of houndstongue is a root-mining weevil, Mogulones cruciger, which was first released in Canada in 1997. The flea beetle Longitarsus quadriguttatus is another below-ground herbivore species considered for the biological control of C. officinale. Previous host-specificity investigations with 49 European test-plant species demonstrated that larval development of the flea beetle is limited largely to plant species within the tribe Cynoglosseae in Boraginaceae. However, investigations neither included any native North American Boraginaceae species nor examined results of earlier tests for plant species that were susceptible to attack by the flea beetle. Therefore, additional host-range investigations were conducted between 1994 and 1996. Different no-choice and choice tests were conducted with 7 plant species that showed susceptibility to attack in previous tests and 5 native North American plant species. Experiments were carried out under laboratory and open-field conditions. L. quadriguttatus was host specific in these tests. Two European test-plant species outside the genus Cynoglossum and 2 native North American Cynoglossum species supported complete development of the flea beetle to some extent, but in all cases the test plants were significantly less suitable hosts than houndstongue. The remaining 5 European and 3 native North American test-plant species did not support development and/or survival of L. quadriguttatus. The introduction of L. quadriguttatus into Canada was approved in 1998.

Huron Smith's ethnobotany of the Hocąk (Winnebago)

The Hocak, commonly known as the Winnebago, are one of the original tribes in the present state of Wisconsin. The field notes of Huron Smith, compiled in the late 1920s and early 1930s, document the extensive use of plant materials by Hocak people. Smith's notes contain references to 199 vascular plant species in 74 families, with recorded uses for 153 of these species. Medicinal plants (with 117 species) comprise the largest category, followed by food (37 species), and fiber and material uses (22 species). Smith's work is unique for its time because he thoroughly explored the tribal uses of the plants in addition to collecting voucher specimens and photographic plates, and because it remains the most extensive Hocąk ethnobotanical study. Added to Smith's other works of tribes in Wisconsin (Menominee, Meskwaki, Ojibwe, and Potawatomi), the Hocak ethnobotany broadens the cultural base of his regional compilation of Native North American plant uses. In addition, this is an important body of information for the Hocąk people and those interested in their use of plants.

Disjunctive Distributions in the Lichen-Forming Fungi

There is a widespread notion among botanists that the nonvascular cryptogams are easily disseminated, ubiquitous plants without well defined geographic ranges. Certainly for many groups, such as the fresh-water algae and the nonpathogenic or nonsubstrate-specific microfungi, this view seems to be justified, for few meaningful geographic-to-taxonomic correlations among these organisms have been perceived. In other groups, for example the higher Basidiomycetes, our ignorance of phytogeographically significant ranges may reflect only the magnitude of the problems inherent in the study of organisms known only from ephemeral sporocarps. There are, however, two large groups of cryptogams in which species and taxa of higher than specific rank show well marked geographic distributions, including disjunctive ones, like those known in the vascular plants. These are the bryophytes and the lichens, the only major groups of terrestrial nonvascular cryptogams in which the vegetative plant body is exposed and perennating. The aim of this paper is to examine disjunction as it is known with regard to the second group, the lichen-forming fungi. Reliable distribution maps have been published for few (only hundreds) of the approximately 20,000 recognized species of lichen fungi. Most of the best substantiated distributions are for conspicuous foliose or fruticose species from temperate regions of the northern hemisphere. To underline the point that lichen fungi may have geographic ranges comparable to those of vascular plants, Table 1 gives eight pairs of common, locally abundant, native North American plants, in each case a lichen fungus and a tree, for which the total geographic ranges are almost congruent or very highly comparable. It should be pointed out that although all but one of the lichen examples are epiphytes, none is ecologically restricted to the bark of the tree species to which its range is compared. Many more such examples could be given from the flora of North America and the floras of Europe and the Far East. So similar in fact are the well documented ranges of lichens to the ranges of vascular plants that the conclusion that both result from the same physioecological and historical factors is inescapable.