Baccharis sergiloides A.Gray (Asteraceae) is a desert shrub found along rivers and in dry washes in and near the Mojave Desert in the southwestern United States. Plants in the species are dioecious, requiring pollen to be transported from male to female florets on different shrubs. I examined the pollination of B. sergiloides in southern Nevada during September 2023 by describing female and male florets and pollen, determining the insects that visit heads of female florets, comparing the relative amounts of conspecific pollen carried by insects, and describing where insects carry pollen on their bodies. The pistil of female florets extends above the tubular corolla and supports two stylar branches. The modified style of male florets is similar and pushes pollen from the anther tube. Nectar was not apparent in florets of either sex. Pollen is 3-zonocolporate with broad, elongated colpi, central apertures, and a microechinate exine. The shape of pollen is suboblate with a mean polar axis of 15 µm and a mean equatorial diameter of 17 µm. Female heads were visited by 13 species of insects in different genera and 9 families in Hymenoptera, Diptera, and Hemiptera. The sphecid wasps Clypeadon evansi Bohart, 1966 and Philanthus gibbosus Fabricius, 1775 (Sphecidae), and the flies Tripanurga aldrichi Parker, 1921 (Sarcophagidae) and Omomyia regularis Curran, 1935 (Richardiidae), were most frequently aspirated. All of the species carried conspecific pollen, and relative amounts of pollen sampled from insects did not significantly differ among species. Insects carried pollen dispersed mostly onto the sides and ventrum of their body. Baccharis sergiloides appears to be pollinated by a variety of unspecialized insects with mostly predaceous or saprophagous larval diets.

This paper examines the occurrence of limb breaks in Salix lasiolepis Benth. (Arroyo Willow) in a natural riparian area, and it explores the morphological and ecological consequences of those breaks. Six S. lasiolepis stands of different ages (0.5–40 yr old) containing individuals of different average sizes (0.3–122 m² crown areas) were studied in the Tijuana River Valley, California. Results showed that limb breaks were common, and their numbers increased significantly with the size of the individual. Most limb breaks were partial, with sufficient vascular connection remaining for the broken limb to survive its break and fall. Each break was examined for the presence of included bark, i.e., a wedge of bark in the limb junction usually considered to be a defect because it weakens junctions and causes junctions to break easily. Included bark was observed in 76% of the limb-junction breaks, and its presence was associated with significantly lower xylem damage and higher survivorship of broken limbs. The ecological consequences of partial limb breaks were considerable. Most fallen limbs remained alive, touched the ground and produced vigorous new growth of epicormic shoots and adventitious roots. The fallen limbs allowed individuals to spread laterally, usurp space, and outcompete neighbors. Over time, repeated limb breaks changed the growth form of S. lasiolepis individuals from upright trees or shrubs to decumbent, clonal sprawlers. This study concludes that, in S. lasiolepis, limb breaks are an integral part of growth and maturation, included bark facilitates survivable limb breaks, and limb breaks are the unusual mechanism by which individuals spread laterally and achieve long-term persistence.

California contains exceptional biodiversity in geography and plant life, including numerous endemic species, some of which are cryptic. The Oenothera deltoides Torr. & Frém. species complex represents a prime example of cryptic diversity. Here, we recognize a new subspecies of Oenothera deltoides, O. deltoides subsp. julpunensis S.F.Jones, subsp. nov., that is a local endemic of windblown sand deposits on the eastern Antioch Dunes sand sheet in the San Francisco Bay-Delta region of California, USA. With the goal of providing clarity to managers of listed species and better understanding of California's diverse flora, we addressed the puzzle of O. deltoides in the region by combining range-wide field surveys with modern genomic tools. We describe the proposed subspecies, its ecology and distribution, and discuss its conservation. As a somewhat cryptic local endemic with small population size and disappearing habitat, the proposed subspecies would benefit from conservation and management to persist as a member of the California flora.