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In the Pacific Northwest, the spotted coralroot, Corallorhiza maculata (Raf.) Raf., has been recognized as occurring as far north as central British Columbia, but excluded from the flora of Alaska. The western coralroot, C. mertensiana Bong., reaches its northern range limit in Southeast Alaska, where collections of this sister species may be confused with C. maculata. In 2019-20, we conducted herbarium and field studies that verified eight C. maculata stations in northern Southeast Alaska. Two of these stations are represented by collections made in 2000 and 2007, which were identified as C. mertensiana; 14 C. mertensiana collections had been identified as C. maculata. This confusion may have resulted from nomenclatural changes, as well as rarity of actual C. maculata material. These species differ in morphological features that reflect different breeding systems, and occupy different habitats in Alaska. The Alaska stations of C. maculata represent a 650 km range extension that is disjunct from locations in central British Columbia. These stations occur in a summer-dry climate zone caused by a rainshadow from coastal mountains. We advance the hypothesis that this area provides habitat for populations of C. maculata that represent relics of a floristic migration that occurred during the Xerothermic interval 10-7500 yr BP. In contrast, C. mertensiana is widespread in humid coastal habitats in southeast Alaska, and its distribution is contiguous with more southern coastal populations. Though both species occur in Southeast Alaska, they occupy different climate zones, and their distributions are narrowly allopatric.
Understanding the germination cues of rare plants is critical to their conservation, restoration, and management. We used a greenhouse study to investigate the germination of Eriodictyon capitatum Eastw. (Lompoc yerba santa) seeds to understand the species' life history and to inform restoration efforts. Eriodictyon capitatum is a woody shrub that is listed as rare by the state of California and endangered by the U.S. Fish and Wildlife Service. Limited to just seven extant occurrences, E. capitatum does not currently readily produce seeds at most sites, but it does spread clonally, sometimes leading to low genetic diversity in aboveground vegetation. We collected seeds from one wild occurrence and measured germination rates in response to each of five physical treatments: control, dry heat, hot soak, liquid smoke, and scarification. Each physical treatment was replicated under both light and dark conditions. The highest percent germination was recorded with the liquid smoke treatment and the fastest germination occurred when seeds were sown in the dark and treated with liquid smoke. The significant impact of liquid smoke on seed germination suggests that E. capitatum is adapted to fire and that periodic fires could potentially promote aboveground genetic diversity by eliciting a flush of germination from the soil seed bank. These results can facilitate future propagation efforts, inform management, and also highlight the important role of fire in the life history of this endangered plant.
Woody plant infections of the pathogenic oomycete Phytophthora ramorum Werres, DeCock, & Manin'tVeld have brought an uncertainty to the future of western forests. Two understory hardwoods, tanoak (Notholithocarpus densiflorus (Hook. and Arn.) Manos, C.H.Cannon, and S.Oh) and California bay (Umbellularia californica (Hook. & Arn.) Nutt.), are commonly infected with P. ramorum leaf infection, the nonfatal foliar form of this pathogen. As the fatal bole infection form of this pathogen is most commonly studied, comparatively little research has been conducted on the nonfatal foliar infection form. This study measured physiological characteristics (midday water potential, stomatal conductance, net photosynthesis, and water-use efficiency) of healthy and infected foliage from tanoak and California bay trees in Redwood National Park to determine the effects P. ramorum foliar infection on leaf-level productivity. For both species, midday water potential, stomatal conductance, and net photosynthesis were all lower in infected samples compared to healthy samples. There was no significant difference in instantaneous water-use efficiency between infected and healthy foliage. Results suggest that P. ramorum leaf infection can lower leaf-level productivity and water status. Further research on the subject is still needed to better support informed management decisions in infected forests and to predict the long-term effects of P. ramorum leaf infections across a diverse suite of host species in the Pacific Northwest.
Cacti with the common name cholla are classified into several genera of the subfamily Opuntioideae (Cactaceae), and appear to be a monophyletic group. Although recent studies have provided strong resolution of the base of this group, assessment of evolutionary processes within genera have been limited due to taxon sampling. Analysis of four spacer and intron sequences of the chloroplast genome reveals evolutionary patterns and trends that are largely congruent with other recent studies. We concur with recent calls for the recognition of Micropuntia pulchella as monotypic and distinct from Grusonia, the name we use to refer to all species sometimes classified under Marenopuntia and Corynopuntia. Grusonia is monophyletic, and Cylindropuntia is borne on two clades of differing branch lengths. By incorporating the elements of ploidy, reproduction, and sequence divergence, we provide new insight into allopolyploid ancestry, the adaptive impact of ploidal-level variation in species, and the role of reproductive mode in diversification rates in the chollas.
A new yellow-flowered annual pincushion, Chaenactis kyhosii B.G.Baldwin, is described from the Central Desert of Baja California, Mexico. This desert taxon has been confused with C. glabriuscula DC. sensu lato (s. l.), a species complex of the California Floristic Province and desert periphery. Chaenactis kyhosii (2n = 5II) is evidently allopatric with C. glabriuscula s. l. (2n = 6II) and is distinct chromosomally. It differs morphologically from other yellow-flowered members of Chaenactis, including C. glabriuscula s. l., by the character-state combination of having non-glandular hairs sparse or lacking, main stem branches concentrated at or near base, leaves mostly basal or proximal on stems, leaf blades entire and filiform or once-pinnate with filiform lobes, peduncles and involucres densely glandular, corollas of marginal florets only slightly enlarged, cypselae sparsely white-strigose to ± glabrate, and pappi uniseriate, of four well-developed, generally unequal, and often obtuse scales. Chaenactis kyhosii is more closely related to the white-flowered, primarily desert-dwelling annual C. fremontii A.Gray, also with 2n = 5II, and the southern lineages of C. glabriuscula s. l. than to the northern lineages of C. glabriuscula s. l.
Cryptantha arenophila Rebman & M.G.Simpson (Boraginaceae) is described as new. This species is restricted to sandy dunes near San Quintín, Baja California, Mexico and adjacent coastal regions. It is similar to the more common Cryptantha patula Greene in stem vestiture, calyx morphology, and inflorescence morphology. Cryptantha arenophila differs from that species in having significantly larger corolla limbs and narrowly oblong to narrowly elliptic leaves with obtuse-rounded leaf apices, as opposed to linear to narrowly lanceolate leaves with acute to obtuse leaf apices in C. patula. In addition, nutlets of C. arenophila tend to have more numerous and shorter tubercles, while those of C. patula have tubercles that are less dense and larger, although variation in this species needs further investigation. The dune habitats where the type locality of C. arenophila occurs are currently under severe impacts from animal grazing and off-road traffic, necessitating the conservation of these regions.
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