Phacelia (Hydrophyllaceae) Juss. is a primarily western North American genus of over 200 annual and perennial species. Historically, calyces in Phacelia subsect. Humiles have provided important taxonomic characters with published descriptions giving mature calyx sizes as ranges rather than a specific number, and with little attention paid to the intra- or interspecific biological significance of this variation. This paper tests the hypothesis that Phacelia sepals are phenotypically plastic organs and that their post-accrescent size in Phacelia subsect. Humiles is related to seed production in associated fruits. Examination of ten taxa within Phacelia subsect. Humiles revealed that calyx size variation within a species was positively correlated with seed weight per capsule for nine of the ten taxa examined. Experimental data showed the correlation was not due to allometry. In defoliation experiments plants grown with all leaves removed post-germination were able to flower and produce seed solely through cotyledon, stem, and calyx photosynthesis, with the sepals expanding in size well beyond normal parameters. This and other data demonstrated that the sepals have developmental plasticity, are important photosynthetic organs, that the seed-weight/sepal-size correlation represents a functionally important source-sink relationship, and that pedicel length and inflorescence density are frequently related to calyx morphological characteristics.

Cirsium wrightii A.Gray (Wright's Marsh Thistle) occurs in boggy soils, closely associated with the rare ciénegas (wet meadows) of New Mexico and often co-occurring with the federally threatened Helianthus paradoxus Heiser (Pecos Sunflower). Both species require full sun in order to mature, but can be shaded and outcompeted by invasive plants. Bitter Lake National Wildlife Refuge (BLNWR), located within the Northern Chihuahuan desert ecoregion, hosts one of the largest populations of C. wrightii and H. paradoxus. Currently, prescribed fire is a management tool used on BLNWR to improve habitat conditions for H. paradoxus, although little is known about how C. wrightii responds to prescribed fire. We conducted a prescribed fire at one of three wetland units populated by C. wrightii to study the effects of fire on growth and survival. We randomly selected 30 plants from the burned unit and five plants from unburned areas to monitor. We used generalized linear mixed effect modeling and Akaike information criterion (AIC_c) model selection to examine the effects of prescribed fire on the weekly growth of plant height and width. We found all plants survived the fire initially and differences in survival at 35 weeks were undetectable between burned and unburned plants. Individual plants within the fire boundary, and those that showed signs of damage due to the fire, grew taller and wider than plants that were not burned or showed no signs of damage. The results from our study will allow managers to improve habitat conditions for two rare and protected species by reducing competition with adjacent plants (including highly invasive species) and increasing the nutrient load in the system.

I present here instructions for the construction and use of a simple hand microtome made from a small brass tube, a steel washer, and a micrometer. The micrometer spindle becomes the specimen advance rod to smoothly push specimens through the tube to its open end, where the washer acts as a cutting guide for razor blade sectioning of specimens. Specimens are held firmly within the tube, wedged between pieces of firm polystyrene foam or a similar material. I present micrographs showing a sampling of plant specimens sectioned using this microtome and briefly discuss the historical origin of its design.

Atriplex gypsophila R.E.Preston is a newly described species that grows on gypsum-rich clay barrens in the Ciervo Hills in central western California. It is morphologically most similar to Atriplex coronata S.Watson and Atriplex vallicola Hoover, but differs from these species by the size and shape of the leaves and diaspores and by the clay barrens or badlands habitat preference, in contrast to the alkali soil habitats where most other annual Atriplex in and adjacent to California's Great Valley occur. Atriplex gypsophila is rare by virtue of its limited distribution and habitat fidelity and merits recognition as a species of conservation concern. Atriplex gypsophila is compared with A. coronata and A. vallicola, two species with which it could be confused, and illustrations of all three species are provided.