Field studies in Butte County, CA, starting in 2009, with more detailed investigations in 2019–2023, indicate that the poorly known Dicentra pauciflora S.Watson (Papaveraceae) is critically reliant upon asexual reproduction from bulblets and rhizomes rather than seed production for survival. This is in direct contrast to two other geophytic Dicentra species at the same sites which use both seeds and underground structures for reproduction. After snowmelt, D. pauciflora proceeded from leaf emergence to flowering and senescence in only 5 to 6 wk. Flowering was infrequent, with the number of flowers at one to three per stalk. The mean number of ovules was 26.8 to 32.3 per flower in three survey years, and very few matured into ripe seeds. Of the ovules, 98% were undeveloped, and seed set was below 2%. However, field plantings of rhizomes and bulblets demonstrated this successful means of asexual reproduction in D. pauciflora. Measurements of the sizes and types of rhizomes and bulblets in flowering and nonflowering plants suggest that it may take a decade for this species to flower. Total rhizome length of 30 to 36 mm was found to be a likely minimum requirement for flowering. Slow growth, primarily by underground rhizomes, may limit dispersal within its range in California and southern Oregon. Rhizomes and bulblets averaged 2.4 cm deep in the soil beneath the forest duff and survived the Dixie Fire in 2021 at the study sites. Underground growth is perhaps one important factor to its long-term survival in the changing environment of northern California.

The Bennett Juniper (Juniperus grandis R.P.Adams, Cupressaceae) in the Sierra Nevada Mountains of California is the largest known individual juniper tree of any species, and thought to be the oldest. I present a revised estimated age for the tree based on an extrapolation of mean annual radial growth rate of ring widths measured from a long increment core containing 1221 rings (769–1989 CE), extended back in time to an inferred pith position based on half of the tree diameter. The pith date estimated from growth extrapolation is 140 BCE, making the tree 2129 yr old when sampled in 1989 CE, or 2164 yr old in 2024 CE when it is still alive. I also obtained radiocarbon dates on three pieces of wood that had been excavated from inside the tree bole by marmots. Radiocarbon dates are all younger than the extrapolated pith date from the increment core, with calibrated dates ranging from 105–280 CE. These dates provide minimum ages for the tree and support for an older pith date. Inexactitude in extrapolating early growth rates coupled with an uncertain pith position relative to where the long core was collected leads me to propose a revised estimated age range for the Bennett Juniper of between 2000–2300 yr. This is younger than an age of 3000 yr often assigned to the tree and younger than another Sierra Juniper known to be 2675 yr old at the time it was cored. However, regardless of inaccuracy inherent in extrapolation methods used here, the Bennett Juniper is undoubtedly one of the oldest known individual trees of any species to be found anywhere in the world.

Trees and shrubs are the main forms of plant cover on ultramafic soils of the southern exposure of the Rattlesnake Creek terrane (RCT) in the Klamath Mountains. A detail soil survey of the ultramafic soils revealed differences in the extent of green conifer tree canopy cover related to soil depth and altitude on the cool and cold soils. The green conifers were Jeffrey Pine (Pinus jeffreyi Balf.), Incense Cedar (Calocedrus decurrens [Torr.] Florin), Douglas-Fir (Pseudotsuga menziesii [Mirb.] Franco), and Sugar Pine (Pinus lambertiana Douglas) on cold soils. Warm soils, at less than about 1000 m altitude (asl) east of Tedoc Mountain to <800 m asl west of Hyampom, lack conifers other than Gray Pine (Pinus sabiniana Douglas). Green conifer cover areas increase from 0% on the warm soils to >40% on cold soils of the Hyampom-Tedoc Mountain area. Farther west in the RCT, the smaller Brannon Mountain-Hoopa area had more landscape and plant community disturbance and less altitude-conifer canopy cover relationships. The conifer tree canopy cover-soil depth relationship in the Hyampom-Tedoc Mountain area is more pronounced than on cool and cold soils in most other parts of the Klamath Mountains. The differences are greater between very shallow and shallow soils than between shallow and moderately deep soils. The differences are expected to be even less pronounced between moderately deep and deep soils, but there were too few deep soils to test this hypothesis effectively. Gray Pine was the only conifer on the warm ultramafic soils and it prevailed in chamise chaparral from below Tedoc Mountain toward the Yolla Bolly Junction at the northern end of the Coast Ranges fault.

Lewisia taylorii J.O'Brien, C.M.Guilliams, S.A.Puentes, & L.Lindstrand (Montiaceae) is described as a new species from northern California. The new taxon is a low, scapose perennial herb growing from a short, thick, single or multi-branched fleshy taproot. When discovered, the taxon best fit the description of L. kelloggii K.Brandegee subsp. hutchisonii Dempster, though morphological traits visible in the field suggested it might be a novel species. Recent morphometric and genetic analysis confirmed this suspicion. The new species is currently known from four general areas in the eastern Klamath Ranges of northeastern Trinity and northwestern Shasta counties, where it occurs on open, often disturbed gravelly-shaley slopes in conifer forest habitat. We describe the morphological and habitat characteristics for L. taylorii and distinguishing characters of L. taylorii and L. kelloggii.