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RAIN + SUN = WILDFLOWERS

That's one of the truisms of life in a Mediterranean climate such as ours. The official water year as measured by NOAA runs from 1 October through 30 September, and along the central/northern California coast most of the rain falls from December through March. The rest of the year, April through the summer and most of the fall, is the long dry season.

Plants that have evolved to live in Mediterranean climates respond quickly to water when it is available. For many annual plants, this means rapid growth in the spring when the soil begins to warm up and the days are getting longer, followed by a burst of flowering as the plants complete their life cycles. Once the rain stops falling there is no water except what is stored in the ground, out of reach for most shallow-rooted plants. The annuals take advantage of the short window between the end of the heaviest rains and the onset of yearly drought to bloom and have sex (i.e., set seed). From 2011-2015 there was moderate to severe drought through most of the state and spring wildflower blooms were anemic and less-than-spectacular. In April 2016, after the El Niño rains of the previous season, some friends and I went down to southern California to check out the bloom. We had made a day trip of it, and it was a very long day that didn't allow for much meandering or poking around. This year we had read from several sources that the heavy winter/early spring rains followed by sunshine would result in a very strong superbloom and managed to squeeze in a 3-day trip, which allowed us to visit more places and change our plans at the last minute if we heard about something interesting to see.


Day 1 (Thursday 23 March 2017): Shell Creek Road 

Shell Creek road is the little road that runs north-south from the hamlet of Shandon to the northwest corner of the Carrizo Plain. The roadbed runs along a little creek that meanders through rolling hills dotted with oak trees. It is really pretty when covered with grasses and wildflowers in the spring, although it will be hot, dusty, and brown for half the year. This is where we caught our first glimpses of the superbloom in action.

Wildflower bloom along Shell Creek Road in San Luis Obispo County
23 March 2017
© Allison J. Gong
Wildflower bloom along Shell Creek Road in San Luis Obispo County
23 March 2017
© Allison J. Gong

The dominant color of the landscape is yellow. A quick thumb-through of any western wildflowers field guide will confirm this. We do have a plethora of yellow flowers in California. In fact, one of the hypothesized reasons California is referred to as "the golden state" is the flood of yellow that carpets hills and valleys in the springtime. The other hypothesis I've heard is that "golden" refers to the color of the hills during the long dry season. Both of these seem feasible to me.

So who's responsible for all this yellow?

The main culprit is the aptly named goldfields (Lasthenia californica). They are very common members of the daisy family, the Asteraceae, and are found in most regions of the state except at higher elevations in the Sierra Nevada.

Goldfields (Lasthenia californica) along Shell Creek Road in San Luis Obispo County
23 March 2017
© Allison J. Gong

Another goldfield look-alike is a flower with the strange common name of Bigelow's tickseed. Its real name is Leptosyne bigelovii. It's a California endemic, found only in the southern half of the state. I looked at a lot of photos, mine and others', trying to learn how to distinguish between the tickseed and goldfields, and hope I have it right.

This is Bigelow's tickseed:

Bigelow's tickseed (Leptosyne bigelovii) along Shell Creek Road in San Luis Obispo County
23 March 2017
© Allison J. Gong

See the differences in flower morphology? I've got samples of each species (I hope!) drying in the plant press, and should be able either to confirm or refute my identifications once I can take a look at them. It's always a good idea to calibrate my intuition whenever I can.

A third yellow flower, which occurs throughout the coastal mountains but we saw only at Shell Creek Road, is the delightfully named coastal tidy tips (Layia platyglossa). This is the kind of common name that makes me smile. You'll see why.

Coastal tidy tips (Layia platyglossa) along Shell Creek Road in San Luis Obispo County
23 March 2017
© Allison J. Gong

Perhaps the tidy tips form large dense patches more readily at other locations, but this year we saw them mostly interspersed among the goldfields. They are conspicuous enough that I think I would have noticed them if I'd seen them last year. From a macro perspective the white petal tips lend a more creamy yellow color to the landscape, compared to the unrelenting blinding yellow of the goldfields. I had never seen them before, and there's something about those white tips that just tickles my fancy. How could I not be enchanted?

Goldfields (Lasthenia californica) and coastal tidy tips (Layia platyglossa) along Shell Creek Road in San Luis Obispo County
23 March 2017
© Allison J. Gong

As lovely as it was, Shell Creek Road was only the first location we wanted to visit that day. Our ultimate destination was the Carrizo Plain National Monument, in southeastern San Luis Obispo County. More about that shortly.

3

Yesterday I joined some friends on an impromptu day trip to southern California to see the spring wildflower bloom. The El Niño rains had brought forth a "superbloom" this year, and while we didn't have time to go all the way to Death Valley we thought we'd be able to see lots of flowers in closer locations.

Stop #1: Tejon Pass, Tehachapi Mountains

California poppies (Eschscholzia californica) on hillside of Tehachapi Mountains. 2 April 2016
California poppies (Eschscholzia californica) on hillside of Tehachapi Mountains.
2 April 2016
© Allison J. Gong
California poppies (E. californica) on hillside of Tehachapi Mountains.
2 April 2016
© Allison J. Gong

It was interesting to note that we saw poppies only on the south-facing slopes. Wanting to get a closer look we continued on our way.

Stop #2: Cerro Noreste/Hudson Ranch Road above the Maricopa Flats

We stopped briefly in Gorman and got our first close-up look at wildflowers. I got to see my beloved California poppies (Eschscholzia californica), but they were not nearly as abundant as I had hoped.

California poppy (Eschscholzia californica) on roadside hill in Gorman, CA.
2 April 2016
© Allison J. Gong
California poppy (E. californica) on roadside hill in Gorman, CA.
2 April 2016
© Allison J. Gong
California poppies (E. californica) and baby blue eyes (N. menziesii) on roadside hill in Gorman, CA. 2 April 2016 © Allison J. Gong
California poppies (E. californica) and Phacelia ciliata (the purple flowers) on roadside hill in Gorman, CA.
2 April 2016
© Allison J. Gong

The flowers in Gorman weren't as spectacular as we had hoped, and in the interest of expediency we didn't take much time to explore a site that didn't look promising. We crossed I-5 and headed west through Frazier Park and onto the Mil Potrero Highway, which at some point becomes the Cerro Noreste/Hudson Ranch Road. And along this road we saw purple and yellow/orange flowers.

Purple flowers along road in Gorman, CA. 2 April 2016 © Allison J. Gong
Purple flowers along Cerro Noreste Road above the Maricopa Flats, CA.
2 April 2016
© Allison J. Gong
Purple wildflowers along Cerro Noreste Road above the Maricopa Flats, CA. 2 April 2016 © Allison J. Gong
Purple wildflowers along Cerro Noreste/Hudson Ranch Road above the Maricopa Flats, CA.
2 April 2016
© Allison J. Gong

I took some close-up shots of the purple flowers, hoping to be able to identify them when I got home. They're very pretty! And I was able to determine that they are Phacelia ciliata. They were by far the most abundant blue or purple flowers we saw yesterday.

Baby blue eyes (Nemophila menziesii) in Gorman, CA. 2 April 2016 © Allison J. Gong
Phacelia ciliata along Cerro Noreste/Hudson Ranch Road above the Maricopa Flats, CA
2 April 2016
© Allison J. Gong

Our other orange flower was fiddleneck, Amsinckia menziesii:

Fiddleneck (Amsinckia menziesii) on roadside hill in Gorman, CA. 2 April 2016 © Allison J. Gong
Fiddleneck (Amsinckia menziesii) along the Cerro Noreste/Hudson Ranch Road above the Maricopa Flats, CA
2 April 2016
© Allison J. Gong

Stop #3: Carrizo Plain

Wanting to check out conditions on the Carrizo Plain, we headed northwest on Soda Lake Road. Our first views of wildflowers on the hills looked like they were part of a pastel painting.

Wildflowers on hills of Carrizo Plain. 2 April 2016 © Allison J. Gong
Wildflowers on hills seen from Soda Lake Road, Santa Margarita, CA.
2 April 2016
© Allison J. Gong
Wildflowers on hills of Carrizo Plain. 2 April 2016 © Allison J. Gong
Wildflowers on hills seen from Soda Lake Road, Santa Margarita, CA.
2 April 2016
© Allison J. Gong

On the Carrizo Plain itself, the most abundant flowers were baby blue eyes (N. menziesii) and goldfields (Lasthenia californica). They made large colorful patches on the plain. So pretty!

Fields of goldfields (Amsinckia menziesii) on the Carrizo Plain. 2 April 2016 © Allison J. Gong
Fields of goldfields (L. californica) and Phacelia ciliata on the Carrizo Plain.
2 April 2016
© Allison J. Gong
Fields of goldfields (Amsinckia menziesii) on the Carrizo Plain. 2 April 2016 © Allison J. Gong
Fields of goldfields (L. californica) and Phacelia ciliata on the Carrizo Plain.
2 April 2016
© Allison J. Gong

Goldfields are not called "goldfields" without reason:

Goldfields (L. californica) on the Carrizo Plain. 2 April 2016 © Allison J. Gong
Goldfields (L. californica) on the Carrizo Plain.
2 April 2016
© Allison J. Gong
Goldfields (L. californica) on the Carrizo Plain. 2 April 2016 © Allison J. Gong
Goldfields (L. californica) on the Carrizo Plain.
2 April 2016
© Allison J. Gong
Goldfields (L. californica) on the Carrizo Plain. 2 April 2016 © Allison J. Gong
Goldfields (L. californica) on the Carrizo Plain.
2 April 2016
© Allison J. Gong
Goldfields (L. californica) on the Carrizo Plain. 2 April 2016 © Allison J. Gong
Goldfields (L. californica) on the Carrizo Plain.
2 April 2016
© Allison J. Gong

I had never made a trip specifically to see wildflowers before, and although it was a 16-hour day and my allergies and asthma are horrible today, it was totally worth it. The fleeting spring wildflower bloom is one of the things that makes California special. In a state with a Mediterranean climate, this short period of blatant reproduction before the onset of the dry season is a pretty magnificent thing to witness.

1

One of my agenda items for spring break this week was to return to Elkhorn Slough and finish the hike that I started with my students a couple of weeks ago. I got out there only to be forcibly reminded that the visitor center, where the hike originates, is closed on Mondays and Tuesdays. Since I'd driven out there, I figured I might as well poke around the area and see what else would catch my eye. I ended up at Kirby Park, a public access area where kayaks put into the water. The tide was out when I arrived, shortly before noon, and the flats were occupied by foraging birds.

Shorebirds and gulls foraging at Kirby Park. 29 March 2016 © Allison J. Gong
Shorebirds and gulls foraging at Kirby Park.
29 March 2016
© Allison J. Gong

I was able to identify birds that forage in the water (avocets, northern shovelers, cormorants, and grebes) and birds that forage in mud (willets, marbled godwits, yellowlegs, and whimbrels), and there were others that I couldn't see well enough to ID. I didn't even really try with the gulls. I do know they weren't either western or California gulls, but that's about it. Someday I may be able to tackle the gulls, but with their multiple juvenile plumages they're a notoriously tough group to figure out.

Many areas of Elkhorn Slough have been invaded by the Japanese mud snail Battilaria attramentaria. This snail was accidentally introduced into the area as tag-alongs on Asian oysters that were imported for mariculture. Battilaria aren't very big, reaching lengths of about 30 mm, but they can occur in astounding densities. A researcher at the slough has documented how this invasive snail came to be so prevalent, and how it has affected the native California snail Cerithidea californica. From the boardwalk trail at Kirby Park I could look down and see many Batillaria in the exposed mud flat.

The invasive Japanese mud snail, Battilaria attramentaria, on the mud flats at Kirby Park. 29 March 2016 © Allison J. Gong
The invasive Japanese mud snail, Battilaria attramentaria, on the mud flats at Kirby Park.
29 March 2016
© Allison J. Gong

This isn't a particularly dense group of Battilaria, either. Across the highway towards the ocean there are mud flats that, when the tide is out, appear to be carpeted with wood chips; all the "wood chips" are the shells of living or dead Battilaria.

One of the Slough inhabitants that I find very interesting is the plant Cuscuta pacifica, commonly referred to as marsh dodder. Dodder is a parasitic plant, and at Elkhorn Slough its main host is pickleweed (Salicornia pacifica). Pickleweed is a perennial succulent that dies back in the winter; it is now beginning to regrow into the mounds that will be the predominant plant in the salt marshes of the Slough.

The first time I saw dodder I thought that some clown had vomited a can of orange Silly String over the pickleweed. I still think that's what it looks like:

Salt marsh dodder (Cuscuta salina) on its host plant pickleweed (Salicornia virginica). 29 March 2016 © Allison J. Gong
Salt marsh dodder (Cuscuta pacifica) on its host plant pickleweed (Salicornia pacifica) at Kirby Park.
29 March 2016
© Allison J. Gong

One of the clues that something interesting is going on with dodder is the orange color. We are used to thinking of plants as being green, or at least green-ish, because they are photosynthetic. Dodder, on the other hand, is a parasite and lives off the tissues of its host; it therefore has no need for chlorophyll, the green molecule that captures light energy used to fix carbon into organic molecules. Looking more closely at the structure of dodder gives you an idea of how it makes a living:

Dodder and pickleweed at Kirby Park. 29 March 2016 © Allison J. Gong
Dodder (C. pacifica) and pickleweed (S. pacifica) at Kirby Park.
29 March 2016
© Allison J. Gong

Dodder consists primarily of orange tendrils that wrap around the host plant. The tendrils penetrate into the vascular tissue of the host and begin withdrawing phloem (the syrupy solution of sugars) from it. Once the dodder has established this internal connection with the host, its own roots die and the dodder becomes entirely dependent on the host. A single plant of dodder can send its tendrils around multiple host plants. From an evolutionary perspective it is impossible to believe that host plants such as pickleweed don't have defenses against dodder. They may be able to repel the tendrils by producing noxious chemicals, but this is a topic that hasn't been well studied. Somebody needs to fix that, as inquiring minds want to know.

Dodder (C. pacifica) on pickleweed (S. virginica) at Kirby Park. 29 March 2016 © Allison J. Gong
Dodder (C. pacifica) on pickleweed (S. pacifica) at Kirby Park.
29 March 2016
© Allison J. Gong
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