CAPITULUM: The International Compositae Alliance Newsletter

In pursuit of Layia DC. (Madieae): Unexpected insights from field work in the land of little rain

Isaac Lichter-Mark

https://orcid.org/0000-0003-3575-6003

Bruce Baldwin

https://orcid.org/0000-0002-0028-2242

DOI: https://doi.org/10.53875/capitulum.01.1.09

Keywords: budding speciation, drought, fire, Mojave Desert

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Abstract

Whole-genome phylogeographic studies of widespread annual Compositae can require dense population sampling across large geographic ranges, yet such plans are increasingly vulnerable to compounded disturbances. This field report documents attempts to collect 100 spatially separated populations of Layia glandulosa (Madieae)—a geographically widespread, self-incompatible annual—and its narrowly endemic derivative L. discoidea, a serpentinite specialist inferred to have arisen via budding speciation (with L. discoidea nested within L. glandulosa in phylogenetic analyses). Fieldwork was delayed by COVID-19 restrictions and then confronted by exceptional climatic and disturbance conditions in California, including record heat, widespread lightning-ignited fires, smoke, land closures, and a La Niña–associated failure of winter–spring rains, yielding one of the driest spring seasons in recent memory. Despite extensive searching of predicted microhabitats, collecting success was initially limited, and ex situ germination from previously banked seed accessions provided critical contingency material. Ultimately, opportunistic discovery of unexpected bloom events in recent burn scars—particularly within Joshua tree woodland affected by the Dome Fire in the Mojave—revealed that post-fire nutrient pulses could coincide with localized wildflower flushes even under extreme drought. Mapping and targeting burn scars subsequently improved sampling efficiency and enabled completion of population-level collecting goals. These observations underscore how integrative use of prior seed resources, citizen-science occurrence data, and disturbance-history reconnaissance can mitigate field constraints and, unexpectedly, generate biological insight into recruitment windows and resilience under interacting drought–fire regimes.