As my internship comes to an end, I am compelled to recognize those that ultimately made it possible for me to collect native plant seed for the last six months : pollinators. Some are opportunistically promiscuous while others are extremely specialized in the plants they pollinate. Through natural selection, plants evolve morphological traits that attract the most efficient pollinators. Similarly, pollinators may evolve morphological traits that allow them to harvest floral resources more efficiently from their favored plants. This relationship is referred to as coevolution.
My internship has exposed me to interesting examples of these relationships. Hesperoyucca whipplei is pollinated exclusively by the yucca moth, Tegeticula maculata, in San Diego county. In addition to pollinating this plant, the female moths deposit eggs into the ovaries of the female yucca flowers. The larvae then feed on the developing seeds and hatch to start the cycle over again. Since only a fraction of the total seeds are consumed, this is a self-perpetuating system. These two species are completely dependent on each other for survival and propagation.
Another interesting tale of pollination in San Diego county is that of Mimulus aurantiacus. This species has yellow phenotype predominant inland and a red one predominant towards the coast. The yellow one is pollinated by hawkmoths while the red one is pollinated by hummingbirds. This shows how different phenoytpes of a single species might have been selected for in areas dominated by different viable pollinators. Interestingly, as these two pollinators broaden their geographic range, so do their respective favorite Mimulus phenotypes.
The preceding was another biological lesson I was fortunate enough to encounter on this internship. While I didn’t actually get to see Mimulus getting pollinated, I got to see some yucca moth larvae emerging from yucca seed. Don’t worry, most of the seed was still viable for shipping. I want to take this opportunity to also thank all the humans that made this awesome internship possible. I had a great time. Now it’s time for me to head back to the redwoods.
-Miguel K.

Erigonum fasciculatum at El Capitan Open Space preserve

This internship has provided a lot of new experiences and opportunities for learning. Specifically, events during the collection of Eriogonum fasciculatum seeds at El Capitan open space preserve compelled me to review some basic biological concepts regarding speciation.
The whole exercise began when Lauren (my internship colleague) and I went on a seemingly routine mission to collect Eriogonum seeds. By the time we each filled a quarter of a bucket with seeds and associated material, Lauren pointed out extensive variation in the leaf morphology of the plants we were collecting. Some plants had linear light green leaves while others had much wider, blue green, tomentose leaves. To make matters more confusing, some plants had shoots exhibiting both leaf types. This made us think there was hybridization of some sort going on so we decided to do some further research before packaging this collection in order to ensure we had taxonomically uniform specimens.
Upon consulting the natural history museum’s plant atlas, we learned that there are three varieties of Eriogonum fasciculatum in the area we were sampling. These are var. fasciculatum, var. foliolosum, and var. polifolium. According to the Jepson manual, var. polifolium has the wider, oblanceolate, tomentose leaves while var. foliolosum has the linear leaves which aren’t nearly as wooly on their upper surface. While var. faciculatum also occurs in the area, I didn’t find clear examples like I did the other varieties. Consequently, we inferred that the individuals we encountered were vars. foliolosum, polifolium, and mixes thereof.
Although we determined the collection was not useful to us because we needed seeds whose varietal lineage was free of co-mingling, this left me with some fundamental questions. How come these morphologically distinct populations are not classified as different species ? What is the difference between a species and a variety ?
Lauren Riesberg, in her extensive writings addressing speciation and hybridization, cited Mayr’s definition of a species as a “groups of interbreeding natural populations reproductively isolated from other such groups”. However, species that are not geographically isolated have been known to interbreed and produce hybrid offspring. Wikipedia defines a variety as a genetically, and in turn, morphologically distinct subset of a species that is geographically isolated from other populations within that species. However, when the geographic barrier is removed, this subset will interbreed with the rest of the species, resulting in an influx of genes which will erode the variety’s distinct features, thus reintegrating it into the greater species group. With this in mind, I distinguish species and varieties based on the fact that a hybrid of two species will produce offspring with reduced fertility, such as malformed pollen grains, while a hybrid of two subspecific varieties will produce offspring that show no such deformities and will reflect the traits of the original species. This concept reflects the methodology Michael Mesler uses in his assessment of hybridity.
In light of these considerations, I came to the conclusion that El Capitan open space preserve is a very special place in the origins and family history of Eriogonum fasciculatum . According to Flora of North America, Eriogonum fasciculatum var. folilosum came about from an ancient hybridization event between vars. fasciculatum and polifolium. This event likely happened at a place much like El Capitan open space reserve, where these populations intermingle. Eventually, isolated populations of these varieties might inbreed to the point that they become reproductively isolated from the parent varieties, giving rise to new species through divergent evolution. El Capitan offers a living snapshot into the evolutionary history that drives speciation. In conclusion, this experience reminds me that speciation is a dynamic process taking place in our backyards, in present times, while we go about our daily lives.

-Miguel K., Escondido, CA

The first Pacific storm finally arrived here last week. While wetter than I expected, it was still warmer than what I’m usually exposed to in Humboldt county. Harvesting Malosma laurina seeds in the rain while climbing on the rocks was very refreshing. After the storm, the climate changed back to summer without missing a beat. Things are still blooming and seeds are still being collected. The botany party just don’t stop down here, ever. I can now see why this is the most botanically diverse county in the nation.

This internship has, for the first time, exposed me to work involving organisms that move around. This makes it interesting to identify them. I’ve been helping with Cactus Wren surveys in the reserve adjacent to the San Diego Zoo safari park. I’m still having a great time experiencing life in this interesting place far from home.

The last three months have flown by quickly. I’m having a great time down here. The perfect weather complements this learning experience nicely. The temperature is way milder than I counted on.
I finally ran into my first rattle snake in the field. I saw it on its “morning commute” to get some breakfast. It didn’t even notice me as it cruised through a patch of Xylococcus (ericaceae).
I have also been doing very interesting things aside from seed saving. This week involved habitat monitoring in the order of vegetation surveys in a reserve to which endangered kangaroo rats are relocated. This is one of the first vegetation surveys I have ever taken part of and am grateful for the experience.
Overall, I am having lots of fun learning new things in the pacific southwest.

This week has reminded me of the inherent divergence between human and plant scheduling.  Twice this week, I ventured to the field thinking I was going to collect a particular species and returned with a different collection than anticipated.  First, I went to the field expecting to get Malosma but instead got Hesperoyucca. Secondly, I went in search of Ceanothus and returned with Arctostaphylos (Manzanita).

The Arctostaphylos seed harvest was one of the funnest things I did in the last couple of weeks.  It took place on a 50% slope overlooking a valley.  I also gave the seeds a taste test, and they were surprisingly delectable. They tasted like rose hips. I am thinking about making Arctostahylos mead in the future.  I am having a blast collecting lots of seed in this bioregion that is new to me.

My first month out of the redwood fog in Northern California has been a great learning experience.  Its been great learning the plants of this bioregion,  starkly different from where I came, characterized by the chaparral plant community.  I am truly grateful to be able to spend my days looking for plants, gathering seed, and cleaning seed.  This station is full of motivated people with various projects one can plug into such as cactus wren habitat monitoring and kangaroo rat habitat restoration.  I didn’t realize other members of anacardiaceae occured in California, so it was cool to meet the genera rhus and malosma.  There are a lot of scenic mountain areas here, more than I thought, in a place I thought was just strip malls and urban sprawl.  It is refreshing to note how much biodiversity still exists in San Diego county. I look forward to further exploration of this new, mediteranean-style home.