Otfinowski, R., Kenkel, N. C. and Catling, P. M. 2007. The biology of Canadian weeds. 134. Bromus inermis Leyss. Can. J. Plant Sci. 87: [183][184][185][186][187][188][189][190][191][192][193][194][195][196][197][198]. Smooth brome (Bromus inermis Leyss.), a native of central Eurasia, was introduced to Canada as a forage and hay crop around 1888. Early reports of plants escaped from cultivation appear in 1903, and based on the number of collections prior to 1920, smooth brome spread most rapidly in western Canada. It is common along roadsides, forest margins, clearings, shorelines and disturbed areas, but its most detrimental impact is on the diversity of prairies and native grasslands. For example, in Riding Mountain National Park, MB, plant diversity of fescue prairies recently invaded by smooth brome decreased by 70%. Vegetative proliferation through underground rhizomes is key to the invasiveness of smooth brome, but long-range dispersal of seeds is facilitated by animals, wind and the transport of hay. Smooth brome is effectively controlled using selective applications of glyphosate and well-timed clipping. However, restoration of infested areas depends on the composition of native seed banks. Smooth brome remains valuable as a forage and cover crop in every province and territory in Canada. [183][184][185][186][187][188][189][190][191][192][193][194][195][196][197][198]. Le brome inerme (Bromus inermis Leyss.), plante indigène du centre de l'Eurasie, a été introduit au Canada pour la production fourragère vers 1888. Les premiers rapports mentionnant des plants retournés à l'état sauvage datent de 1903. D'après le nombre de prélèvements effectués avant 1920, on constate cependant que l'espèce s'est répan-due plus rapidement dans l'ouest du pays. Le brome inerme colonise souvent le bas-côté des routes, la lisière des bois, les clairières, les rivages et les terres perturbées, mais l'espèce nuit le plus à la diversité de la flore des prairies et des pâturages naturels. Dans le parc national Riding Mountain, au Manitoba, on a noté une diminution de la diversité des plantes de 70 % dans les prairies à fétuques récemment envahies par le brome inerme. L'efficacité du brome inerme vient essentiellement de sa reproduction végé-tative par rhizomes, mais les animaux, le vent et le transport du foin favorisent la dispersion des graines sur de grandes distances. L'application sélective de glyphosate et une coupe opportune permettent une lutte efficace contre cette adventice. Toutefois, la restauration des lieux infestés dépend de la composition des réserves de semences indigènes. Le brome inerme garde son utilité comme culture fourragère et culture abri dans toutes les provinces et tous les territoires du Canada. Mots clés: Bromus inermis Description and Account of Variation(a) Description. Rhizomatous perennial, 2-15 dm tall, the culms topped with open panicles 5-20 cm long with ascending or spreading branches. Rhizomes up to 1.5 m long without branching or producing stems, 2-5 mm wide, with pale scales. Culms smooth...

Premise of the study:Constructing complete, accurate plant DNA barcode reference libraries can be logistically challenging for large-scale floras. Here we demonstrate the promise and challenges of using herbarium collections for building a DNA barcode reference library for the vascular plant flora of Canada.Methods:Our study examined 20,816 specimens representing 5076 of 5190 vascular plant species in Canada (98%). For 98% of the specimens, at least one of the DNA barcode regions was recovered from the plastid loci rbcL and matK and from the nuclear ITS2 region. We used beta regression to quantify the effects of age, type of preservation, and taxonomic affiliation (family) on DNA sequence recovery.Results:Specimen age and method of preservation had significant effects on sequence recovery for all markers, but influenced some families more (e.g., Boraginaceae) than others (e.g., Asteraceae).Discussion:Our DNA barcode library represents an unparalleled resource for metagenomic and ecological genetic research working on temperate and arctic biomes. An observed decline in sequence recovery with specimen age may be associated with poor primer matches, intragenomic variation (for ITS2), or inhibitory secondary compounds in some taxa.

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Most northeastern North American Spiranthes are adapted to pollination by long-tongued bees (e.g., Bombus spp. and Megachilidae). The salient features of this adaptation are (i) a long, flat viscidium which attaches the pollinia readily to the flat rigid galea of the insect's proboscis, (ii) the nectar secreted into the base of the floral tube, (iii) the flowers are protandrous and sequential beginning at the base. In contrast, Spiranthes lucida apparently is pollinated largely by halictine bees. It differs from other northeastern taxa of Spiranthes in (i) having an oval viscidium which attaches the pollinia to the clypeus below the antennae, (ii) having the nectar available on the under side of the column behind the stigmatic surface, and (iii) in lacking protandry. In the characteristically Bombus-pollinated taxa, protandry is accomplished by a change in the position of the terminal portion of the column with respect to the lip, apparently due to cell elongation in both the column and the lip. The present investigation documents protandry in S. cernua var. cernua, S. lacera var. lacera, S. lacera var. gracilis, S. laciniata, S. magnicamporum, S. ochroleuca, S. romanzoffiana, S. tuberosa, and S. vernalis. Bees moving up the spike from the older female flowers to the younger male flowers act initially as pollen donors and later as pollen receivers; thus cross-fertilization is enhanced. Halictines occasionally act as pollinators of characteristically Bombus-pollinated taxa by visiting the flowers upside down so that the pollinia are inconspicuously attached to the lower side of the prementum. Data presently available for northeastern North American Spiranthes fail to establish pollinator specificity as significant in speciation except perhaps with respect to the separation of S. lucida from the other 14 northeastern taxa.

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