Premise of research. The lianoid habit is found in 125 extant plant families and is most diverse and abundant in structurally complex forests, such as tropical forests. A stem with lianoid anatomy is described from Cretaceous sediments of Hornby Island, British Columbia.
Methodology. The stem segment, 2.5 cm in diameter...
Primula sect. Parryi comprises five species endemic to western North America: P. parryi, P. angustifolia, P. rusbyi, P. capillaris, and P. cusickiana with four varieties. This section, derived from a clade with representatives in Asia and Europe, exemplifies a phytogeographic pattern in which a widespread species is accompanied by multiple...
A new photosystem-II mutant of the green alga Scenedesmus
obliquus D₃, strain PS-28, has been shown to lack a-tocopherol
(vitamin E). The photosynthetic activity of dark grown samples of
PS-28 is about 20% of the wild-type control. Culturing the mutant
at low light intentisites (10⁴ ergs/sec-cm ²) stimulates photosynthetic
activity...
A perithecial ascomycete, Spataporthe taylori gen. et sp. nov., represented by >70 sporocarps is preserved by
cellular permineralization in marine carbonate concretions dated at the Valanginian-Hauterivian boundary (Early
Cretaceous) from Vancouver Island, British Columbia, Canada. The spheroid perithecia with lumina 330–470 µm
wide and 220–320 µm high are densely distributed...
Reexamination of fossilized plant material from the westernmost Pennsylvanian-age wetland flora in North America reveals that material of Pecopteris oregonensis Arnold represents a filicalean fern frond with annulate sporangia and anatomically preserved vascular tissues of the rachis. The frond, which is redescribed as Senftenbergia oregonensis (Arnold) Hillier et Rothwell comb....
Laboratory-based methods to test egg viability include staining with Meldola's Blue and/or juvenile (J2) hatching assays using potato root diffusate (PRD). These two methods have not been tested under identical conditions to directly compare their assessments of Globodera egg viability. Using two bioassay strategies, cysts from a Glabodera sp. population...
The purpose of this study was to investigate the effects of
logging on the productivity, structure and biomass of a periphyton
community developed in mountain streams. The three streams used
in this investigation were located in the coast range of Lincoln
County, Oregon. They were selected for similarity of habitat,...
Trade in live plants has been recognized worldwide as an important invasion pathway for non-native plant pests. Such pests can have severe economic and ecological consequences. Nearly 70% of damaging forest insects and pathogens established in the US between 1860 and 2006 most likely entered on imported live plants. The...
The particulate optical backscattering coefficient (bbₚ) is a
fundamental optical property that allows monitoring of marine suspended
particles both in situ and from space. Backscattering measurements in the
open ocean are still scarce, however, especially in oligotrophic regions.
Consequently, uncertainties remain in bbₚ parameterizations as well as
in satellite estimates...
We investigated habitat attributes related to the occupancy of the globally rare and endangered
epiphytic lichen, Erioderma pedicellatum, in a newly discovered (2009) population center in Denali National
Park and Preserve (DNPP), Alaska. We measured forest, tree and epiphytic lichen community
characteristics on eighty-five systematically selected plots in four study...