Frankenia is the sole genus within the Frankeniaceae, or the sea heath family. This flowering plant family has a distribution that covers warm, dry areas of most continents, though the majority of species are Australian. Typically, plants in this family are associated with soils that are either saline, calcareous, or gypsum-rich.
Frankenia salina, as you might guess from the epithet, grows in salt-rich soils. The Flora of North America account for Frankenia salina has it native to the USA (California and Nevada), México, and Chile in “saline and alkaline soil, salt marshes, [and] alkali flats”. While some species are almost strictly coastal, Frankenia salina, or alkali heath, can be found along the coast and inland.
The universal adaptive strategy theory posits that organisms allocate resources among growth (a competitive strategy), maintenance (a stress-tolerant strategy), or regeneration (a ruderal strategy), to wit:
A universal three-way trade-off produces adaptive strategies throughout the tree of life, with extreme strategies facilitating the survival of genes via: C (competitive), the survival of the individual using traits that maximize resource acquisition and resource control in consistently productive niches; S (stress-tolerant), individual survival via maintenance of metabolic performance in variable and unproductive niches; or R (ruderal), rapid gene propagation via rapid completion of the lifecycle and regeneration in niches where events are frequently lethal to the individual.
Quick examples of each: the giant redwoods of California (competitive), the high-altitude plants of the Himalayas (stress-tolerant), and the flashy displays of annual wildflowers in South Africa (ruderal)…
It is impossible for an organism to evolve a survival strategy in which all resources are devoted exclusively to one of these investment paths, but relatively extreme strategies exist, with a range of intermediates. The system can be represented by a triangle, with the three extreme possibilities at its vertices. The different species may be located at some particular point inside this triangle, accommodating a certain percentage of each of the three strategies.
Halophytes (“salt-plants”), like Frankenia salina, are good examples of stress-tolerant plants; they have to deal with the physiological and biochemical challenges of growing in salt-rich environments. Instead of investing in growth, they have to invest in strategies like the ability to excrete salt from tissues (an energy-intensive process, as it requires moving salt against its diffusion gradient). A couple general properties of stress-tolerant plants is they are short in stature (Frankenia salina grows to 60cm (2 ft.)) and occur in light-rich environments (though, of course, there are plants that are tolerant of another stressor–low light environments). See New to Nature No. 127: Frankenia fruticosa for a little bit more on the adaptations of Frankenia.
Today’s entry was inspired by the highlighting of Frankenia salina in the clearly-written California Plants: A Guide to Our Iconic Flora, a new book by BPotD reader and commenter Matt Ritter. It would be an impossible task to produce a field guide to all of California’s plants, because of the exceptional diversity of both plants and environments. In his wisdom, Matt took the approach of addressing the iconic, i.e., “if I think about the redwood forests of California, what are the plants (or plant groups) that come to mind…and if I think about the deserts of California, what are the plants…”. He succeeds in doing so, with the evocative text about individual species or California landscapes complemented by his excellent photographs.