New seaweed finds in central California

At the end of my trip through the southwest, I shifted from National Parks and lizards and desert wildflowers to marine life of the central California coast. At tidepooling stops in Cambria and northern Santa Cruz County, I encountered two new-to-me brown seaweed species, exciting discoveries punctuating my long-term study of natural history and biogeography along the west coast.

The first new species was a high intertidal species of rockweed at Cambria in San Luis Obispo County. Rockweeds are a family of brown seaweeds in the order Fucales. Many coastal visitors (enthusiastic about slimy seaweeds or not) have likely seen these organisms since they tend to be common on rocky shorelines and live high in the intertidal zone where a good low tide isn’t necessary to leave them exposed.

Until recently, five rockweed species were recognized along the California coast (Abbott and Hollenberg 1976; Gabrielson et al. 2004; Gabrielson et al. 2012). These species are Fucus distichus, Silvetia compressa, Hesperphycus californicus, Pelvetiopsis limitata, and Pelvetiopsis arborescens. There have been several changes to the scientific names of the California rockweeds since the publication of the landmark book on California seaweeds (Marine Algae of California; Abbott and Hollenberg 1976), so I’ve included the older Latin names in the table below.

Wandering the west coast, I have seen all five of these species at various points, the rarest being P. arborescens which is only found in the vicinity of Monterey. My visit to Cambria last month was my first encounter with the sixth rockweed species, since it was newly described in the scientific literature in a paper earlier this year (Neiva et al. 2017). Maybe I have seen it before without recognizing it as a distinct species.

Two common rockweed species in California: Fucus distichus (left; Carmel Pt., Monterey Co., 2014) and Silvetia compressa (right; Scott Creek, Santa Cruz Co., 2007).

Traditionally species have been described based on their morphology, but increasingly molecular signatures are complementing, and even upending, traditional concepts of differences between species. Neiva and colleagues examined mitochondrial DNA from Pelvetiopsis and Hesperophycus, identifying a new species of Pelvetiopsis: P. hybrida.

Neiva et al.’s study resulted in some other interesting findings. First, they found evidence that P. hybrida originated because of a relatively recent hybridization event between Hesperophycus californicus and Pelvetiopsis arborescens. Up until this study, the authors note, this type of hybridization (allopolyploidy) has probably never been documented before in brown seaweeds. Polyploidy refers to chromosome multiplication inside the nucleus during a hybridization event (for instance, a hybrid progeny has twice the number of chromosomes as its parents). Allopolyploidy occurs when the two parents are from different species.

Second, the researchers confirmed that P. arborescens is a distinct species genetically, and suggested that its restricted range indicates it is a climatic relict. Finally, they found that the evidence didn’t favor placing Hesperophycus on its own separate branch on the evolutionary tree. Instead this genus seemed to stem from within the Pelvetiopsis branch, meaning that it should be renamed to be a part of that group. Hesperophycus californicus was this renamed to P. californicus in the study. 

Pelvetiopsis spp. along the US west coast. Clockwise from upper left: P. limitata (Dillon Beach, Marin Co., CA, 2008), P. californicus (Cambria, San Luis Obispo Co., 2017), P. hybrida (Cambria, 2017) and P. arborescens (Carmel Pt., Monterey Co., CA, 2017).

All those scientific name changes, annoying as they can be when trying to be a diligent student of natural history, are part of the evolution of scientific understanding and hopefully bring us to a better picture of the true evolutionary relationships among organisms over time. So, the current names for the (now) six species of California rockweeds are below:

Note that Silva et al. (2004) recognize two subspecies of Silvetia compressa: S. compressa ssp. compressa on the mainland coast of North America and S. compressa ssp. deliquescens on the Channel Islands in southern California.

At Cambria, the high intertidal rocks had populations of P. hybrida where it was pretty common. I photographed the species pretty intensely, noting that they seemed different from the usual Pelvetiopsis limitata (this species is the most common and widespread of all the species in the genus where I tend to tidepool), but I wasn’t confident I was really seeing the new species until I returned home and reviewed Neiva et al’s paper. Perhaps unsurprisingly because it is a hybrid lineage, P. hybrida is morphologically intermediate to its parent lineages. It has some cryptostomata (tufts of very small colorless hairs on the surface of the plant) like Hesperophycus, but its branches are narrower, intermediate between the two parental species. 

A mix of four intertidal rockweed species at Point Pinos, Monterey Co., 2016. Can you identify the four species?

~ ~ ~ ~

My second new seaweed find got me really excited. It was a kelp, another group of brown seaweeds in the order Laminariales. Kelps are one of my favorite groups of marine plants and after about two decades of tidepooling along the west coast, I think I’ve seen virtually every species that occurs between San Diego to Washington…except one. That would be the elusive Laminaria ephemera.

I’ve seen L. ephemera as a herbarium specimen to be sure, but until this spring I had never seen it in the wild. The magic location was Greyhound Rock in northern Santa Cruz County.

As I often do during rocky intertidal visits, I was compiling a list of large brown seaweeds (Laminariales, Fucales, etc.) present at the site, when I stumbled upon a few long kelp blades in the low intertidal that didn’t immediately register as a known species. The blades were entire (not divided), long, slender, and simple except for a really pronounced sorus (area of spore production) at the center of the blades. I initially thought of Laminaria farlowii, but the blades of that species are distinctly ruffled all over its surface. And then my mind settled on Laminaria ephemera, a species I had long known about but had never positively identified in the field.

The key feature to identify L. ephemera lies in the holdfast. Unlike most other kelp species, it has a discoid holdfast that lacks haptera (spreading branches that superficially resemble plant roots). The holdfast is essentially a small golden brown suction cup that anchors the plant to a rock. Gently moving aside some of the algal cover around the base of the plant, sure enough, I could see the small smooth holdfast.

Laminaria ephemera at Greyhound Rock, Santa Cruz Co., CA, April 2017. Left: Blades. Right: close-up of discoid holdfast.

The population of L. ephemera I discovered was of unknown size, but it didn’t seem large from my observations. There were about 10 blades that seemed to meet the visual criteria for the species, and I checked about half of those to verify the presence of the correct holdfast. There were smaller kelp blades in the low intertidal that could have been less mature plants of the species, or possibly specimens of L. sinclairii or L. setchellii, both of which were also present at the site. The challenge with identification of the kelps is that the juvenile sporophytes all look terribly similar, regardless of species.

Two blades of L. ephemera with sori (regions of a seaweed blade that produce spores) at Greyhound Rock, April 2017.

How would a large seaweed like L. ephemera be hard to miss? A few reasons perhaps. First, as one of the few annual kelps, L. ephemera would quickly mature and then disappear after several months of growth. It would be an unlikely find in the fall or winter. Second, blades might be easily confused for small plants of L. setchellii (before the blade begins to divide into individual straps) or L. sinclairii. One would have to check every holdfast to distinguish L. ephemera from related kelps. Finally, L. ephemera appears to be fairly rare along the west coast of the US. Abbott and Hollenberg (1976) note that it is present from Alaska to Monterey County, but also call it “infrequent”. Reviewing herbarium records available on-line at the Macroalgal Herbarium Portal, in California this species seems to have mainly been collected from Monterey and Humboldt Counties, so my finding of a small population in northern Santa Cruz County may possibly be a new location for this species. This is a species I’d like to study further in terms of prior collections, and … I need to check more kelp holdfasts in the field!

References

Abbott IA, Hollenberg GJ. 1976. Marine Algae of California. Stanford University Press.

Gabrielson PW, Widdowson TB, Lindstrom SC. 2004. Keys to the seaweeds and seagrasses of Oregon and California, north of Point Conception. Phycological Contribution No 6.

Gabrielson PW, Lindstrom SC, O’Kelly CJ. 2012. Keys to the seaweeds and seagrasses of southeast Alaska, British Columbia, Washington, and Oregon. Phycological Contribution No 8.

Macroalgal Herbarium Portal. 2017. http://macroalgae.org/portal/index/php. Accessed 16 May 2017.

Neiva J, Serrão EA, Anderson L, Raimondi PT, Martins N, Gouveia L,Paulino C, Coelho NC, Miller KA, Reed DC, Ladah LB, Pearson GA. 2017. Cryptic diversity, geographical endemism and allopolyploidy in NE Pacific seaweeds. BMC Evolutionary Biology 17:30.

Silva PC. 1990. Hesperophycus Setchell & Gardner, nom. cons. prop., a problematic name applied to a distinct genus of Fucaceae (Phaeophyceae). Taxon 39:1-8.

Silva PC, Pedroche FF, Chacana ME, Aguilar-Rosas R, Aguilar-Rosas LE, Raum J. 2004. Geographic correlation of morphological and molecular variation in Silvetia compressa (Fucaceae, Fucales, Phaeophyceae). Phycologia 43:204-214.

Black Rock Canyon at Joshua Tree

A Joshua Tree in the lower Black Rock Canyon.

Joshua Tree National Park was the final NPS stop on my April loop through the Southwest. The park straddles the border of the Mojave and Sonoran deserts, the former encompassing the northern part of the park and extending up to Death Valley, and the latter desert encompassing the southern portion of the park.

Arriving after dark after driving through Kingman, AZ, Mojave National Preserve, and a short segment of old Route 66, I camped in the north central part of the park at the Indian Cove Campground. It was not crowded and a lovely spot, encircled about by the large fractured boulders that are one of the common landscape features of Joshua Tree. The morning light revealed all of the flowers present near my campsite, especially yellow patches of Desert Senna. The area looked like a tended garden with rocks and the lovely flora.

Packing up camp, I drove to the northwest corner of the park for a hike up Black Rock Canyon. There is another campground at the trailhead with a series of trails that radiate to the east and south. The canyon is initially wide, sandy, and full of the other iconic feature of the park: Joshua Trees (Yucca brevifolia). I saw (and heard) several quail in this area including a pair or two. The birds quickly scurried to and fro over the ground, not at all interested in getting close to a human.

Quail at Black Rock Canyon.

With some elevation gain heading along the trail to the south, the valleys grew narrower and rockier, and new woody species and more flowers became evident. I first noticed juniper, then pines (Pinus monophylla) and oaks. Joshua Trees were still present, as was the related but shorter species, Mojave yucca (Y. shidigera).

There were many flowers in bloom, including orange desert mallow (Sphaeralcea ambigua), the common desert dandelion (Malacothrix glabrata), bladderpod (Peritoma arborea), and Wallace’s woolly daisy (Eriophyllum wallacei), a tiny yellow aster found in sand along the edges of the trails. I also observed vines and fruits of wild cucumber, a plant not uncommon in the chaparral of coastal California, with its spiked fruits shaped like kiwis. The fruits in this area were particularly large and seemed to be among the largest I’ve ever seen of this species.

Diversity of blooming plants. Clockwise from upper left: Sphaeralcea ambigua (desert mallow), Phacelia sp., Malacothrix glabrata (desert dandelion), Salvia columbariae (chia), Layia glandulosa (white tidy-tips), and Eschscholzia glyptosperma (desert gold poppy). 

Many cacti were in bloom with their very showy flowers. The beavertail (Opuntia basilaris) had large flowers with concentric layers of ruffled pink petals. There were similarly-colored flowers on the hedgehog cactus (Echinocereus engelmannii) and red blooms on the related E. mojavensis. The flowers of the beavertail had a sweet, perhaps fruity, smell that seemed familiar but I could make the association in my mind.

Blooming cacti. Left: Opuntia basilaris (beavertail cactus). Center: Echinocereus engelmannii. Right: E. mojavensis.

The Black Rock Canyon area had an interesting assortment of wildlife too: the quail previously mentioned, many flying insects, chipmunk, and lizard. I had to pass a swarm of bees on the trail that was congregating around the tiniest of water holes seeping from a rock.

More desert fauna. The bees at right were congregating around a very tiny water
seep from a desert rock.

I am still learning about the differences among the various deserts of the Southwest. The Mojave is the smallest and driest of these deserts (MacKay 2013). Various maps show somewhat different boundaries between the southwest deserts, but basically the Mojave Desert stretches from Joshua Tree NP in the south to the Landcaster area in the west, Death Valley National Park in the north, and the southern tip of Nevada and northwest corner of Arizona to the east (Pavlik 2008, Mackay 2013). To the north of the Mojave is the cooler desert of the Great Basin that encompasses most of Nevada, while to the south and east is the Sonoran Desert that stretches south into the Baja and Sonoran regions of northern Mexico.

Two perspectives on the geographic extent of the Mojave Desert and nearby deserts in the US Southwest. My travels through the Southwest took me through the Great Basin, Colorado Plateau, Arizona/New Mexico Plateau, and Mojave Desert. Base maps from the USGS and EPA; in the public domain.

Sunrise at the Indian Cove Campground.

Some characteristic species can help guide one through the various deserts of the region. The Joshua Trees are indicative of the Mojave, occurring in places from NW Arizona to Joshua Tree to the high desert north of Los Angeles. The Sonoran desert has the iconic saguaro cactus (not seen on my trip) and the wonderful ocotillo with its flaming branch tips of red flowers. I did not see ocotillo in the northern part of Joshua Tree (which is Mojave territory), but saw it in abundance at the southern end of the park on a previous trip (that area is Sonoran territory). Interestingly, I also saw a population along Interstate 40 south of Kingman, AZ.

The Mojave Desert has a high diversity of plant species (>2600), a wide range of elevations which provides for a diversity of habitats, and a rate of plant endemism of about 25% (MacKay 2013). Mackay (2013) suggests the area may be under-explored botanically, with the possibility of future plant discoveries.

References

MacKay P. 2013. Mojave Desert Wildflowers. 2^nd ed. Rowman & Littlefield

Pavlik BM. 2008. The California Deserts. An Ecological Rediscovery. University of California Press, Berkeley, CA.

Arizona's canyons and cinder cones

After backpacking for a night in the Petrified Forest, the rest of my time in northern Arizona was a bit of a whirlwind of short visits to a couple of other NPS and BLM sites including Sunset Crater Volcano National Monument, the south rim of the Grand Canyon, Walnut Canyon National Monument, and BLM land near Kingman for wildflowers.

Sunset Crater Volcano is a small monument located just a short distance north of Flagstaff. It features a black and brick red cinder cone that erupted less than a thousand years ago, and an older and shorter volcano. The smooth slopes of the mountain are lightly forested.

View of Sunset Crater Volcano from the west.

The Grand Canyon is of course world famous, though this was my first time ever visiting the park. I didn’t leave much time in my schedule at all that day, so my visit consisted of a few stops at lookout points along the south rim. The canyon is immense, although I’m not sure I was as impressed with the view as I was with the view from Canyonlands NP the week prior in Utah.

Fisheye view of the Grand Canyon from Moran Point on the south rim.

Walnut Canyon.

Walnut Canyon National Monument is another small NPS unit in the Flagstaff area. A canyon several hundred feet deep winds through the area with grey and beige colored striated rock forming the walls of the canyon. Like Mesa Verde and Bandelier, the canyon contains Ancestral Pueblo cliff dwellings which form one of the main attractions of the site. The canyon floor, slopes, and tops of the mesas are forested with juniper, pinyon pine, and Douglas fir. Banana yucca and Opuntia cacti were common.

En route to southern California, my last Arizona adventures were in the Kingman area in the northwest part of the state. Some distance east of Kingman along Interstate 40 I began to notice abundant wildflowers as I was driving, including the orange flowers of desert mallow. So, in Kingman I stopped at the BLM office to scope out some potential places to wander around and I ended up exploring a little along the western slope of the Hualapai Range. I found a diversity of plants in bloom and collected a few small specimens to press in a book. Farther along I40, south of Kingman, I also discovered blooming ocotillo, one of my favorite desert plants. Growing in tall scraggly tufts from the ground, this species cannot be missed even from a fast-moving car, and even less so when it shows off its fiery red flowers.

Left: Forested volcanic field on a slope just west of Sunset Crater Volcano. Right: Bright yellow lichens colonizing volcanic rock.

Whiptail lizard at Walnut Creek National Monument.

Cliff Dwellings at Walnut Canyon. Unfortunately early explorers and collectors damaged many of the dwellings in this area, including using dynamite to knock down the ancient walls.

Colorado River at Grand Canyon National Park from
Desert View on the south rim.