My last couple blog entries have been about very “Californian” taxa, with their centers of diversity in the Golden State. With over 2500 species spread across all 6 of the continents worth botanizing, Astragalus is much more cosmopolitan. Still, California has its fair share, with nearly 100 species (and many more varities). I’ve collected photos of 18.

Astragalus is in the Fabaceae, or pea, family, which is one of the most easily recognizable. Flowers (at least in the subfamily Paplionoidae) have a characteristic bilateral shape, with a large banner petal on the top, two wing petals off to the sides, and two bottom petals fused into a shape resembling the keel of a boat. This close up of Astragalus purshii, a common mountain species shows the flowers well.

Fabaceae is even more recognizable by their pod-shaped fruits called legumes. In many members of Astragalus, these pods are inflated into fun, pop-able pouches. Here they are in Astragalus lentiginosus–in this species, they also happen to be freckled

Finally, this family tends to have compound leaves–in the case of Astragalus they are pinnately compound with leaflets arranged across from each other along a central axis. Look in the background of this lovely Astragalus lanyeae from the Mohave desert.

You can refer to plants in this genus by two different common names. The first, milkvetch, works for all species. But a number of species such as the A. lentiginosus shown above and this Astragalus nuttallii from coastal bluffs in along the central coast, produce a toxic compound called swainsonine.

This compound apparently tastes fine to livestock who will preferentially munch on Astragalus plants. If animals eat to much of it, it causes vacuolation and subsequent destruction of neurons. The resulting abnormal behaviors of poisoned livestock were noticed by ranchers in the 1800’s. They dubbed the plants “locoweed”. Unfortunately for the plant, knowledgeable ranchers will remove Astragalus from their pastures threatening the survival of some of the rarer grassland species.

Most Astragalus (and actually Fabacaeous plants in general) are bee pollinated. The stigma and stamens are enclosed in the keel. When a bee lands on the flower, its weight pushes the keel downward exposing the reproductive parts and allowing for pollination. Butterflies and flies just aren’t heavy enough to trip the keel. Here’s Bombus vosnesenskii pollinating Astragalus oxyphysus, one of the aforementioned threatened locoweeds from San Joaquin valley

The glorious exception to bee pollination in the genus is Astragalus coccineus, found in pinyon pine woodlands in desert mountains. This species makes use of hummingbirds that presumably press down the keel with their chin.

Even more than most taxa in California, Astragalus is a genus of extreme endemism. Many, many species are restricted to a very specific habitat in a very specific area. Even more widely distributed species, such as the A. lentiginosus and A. purshii are further subdivided geographically into varieties. Wherever you are, there’s likely a rare Astragalus near you. Here are just four of my favorite rare Astragalus:

Astragalus tener, a cute little annual specializing on vernal pools in the Bay delta.

Astragalus pycnostachyus, a stout perennial found in a few coastal saltmarshes in San Mateo, Marin, and Humboldt counties (unlike the east coast, there’s just not very much coastal saltmarsh habitat in California, so the few California endemics that specialize in them tend to be very rare).

Astragalus albens, from only the limestone soils of Cushenbury Canyon in the San Bernardinos. I love the strigose (short, appressed) hairs on the leaves, stem, and sepals of this one.

And finally Astragalus ertterae, found only in a approximately one square mile area just west of Walker Pass in the very southernmost Sierras (you have to hike down the Pacific Crest Trail to see it).

I highly recommend playing around on to find the rare Astragalus near you!


Botanizing while birding

The main goal of this weekend was to find some migrating birds, meaning that flowers took a bit of a back seat. The Western Mojave, in addition to having amazing flowers, is one of the better places to find birds traveling from their tropical wintering grounds to the Sierras and points north. Migrants tend to concentrate around places in the desert with trees and water, stopping to recharge during the day and continuing on under the stars. Thus, hanging out at desert oases at dawn in the spring can be pretty fun. Despite the avian focus of the weekend, I did track down some pretty great flowers. I’ll start with the rarest one, Astragalus ertterae (Walker Pass Milkvetch, Fabaceae). This plant is only known from a couple locations around one Mountain pass in the Southern Sierras (which is incidentally also a great place to find some locally uncommon birds such as Pinyon Jay).


I also made it into the San Gabriel Mountains, south of Bakersfield, where I added to my growing collection of Blazing Star photos by finding large fields of Mentzelia gracilenta (Graceful Blazing Star, Loasaceae) mixed in with Gilia capitata abrontanifolia (Ball Gilia, Polemoniaceae)

Besides these two stops, most of the botanizing happened in Eastern Kern County. I’ve already been a couple times this year, but I certainly haven’t run out of flowers. Here are a few relatively common Mojave flowers that were new to me this trip:

Eriogonum nudum westonii (Weston’s Buckwheat, Polygonaceae),


Glyptopleura setulosa (Holy Dandelion, Asteraceae),


and Pensetmon incertus (Mojave Beardtongue, Plantaginaceae).


An uncommon, but somewhat inconspicuous species, Chorizanthe spinosa (Mojave Spineflower, Polygonaceae)


And finally, that great combination of rare and beautiful, Calochortus striatus (Alkali Mariposa Lily, Liliaceae).


Southwestern California

I had so much fun in the Peninsular Ranges last week that I headed that way again. This time, I stay much more coastal, botanizing in a three spots north of San Diego–Mission Trails Regional Park, Torrey Pines State Reserve, and Santa Rosa Plateau Ecological Reserve (confusingly, the Santa Rosa Plateau is not in the Santa Rosa mountains where I botanized last week, nor is it anywhere near the bay area city of Santa Rosa). I chose these locations to be about as different in their vegetation as possible. Mission Trails has fairly typical Coastal Sage Scrub–a chaparral habitat characterized by aromatic shrubs such as Salvia apiana (White Sage, Lamiaceae), and Mimulus aurantiacus var puniceus (Red Sticky Monkeyflower). The later is a hummingbird pollinated coastal form that grades into the more typical orange, bee-pollinated form as you move inland.

These two plants, along with the delightfully abundant Calochortus splendens (Splended Mariposa Lily), were the only species I photographed that were present at all three locations.


A couple bushy pink flowers in the mallow family were blooming in good numbers in the park–  Malacothamnus fasciculatus (Chapparal Mallow), and Sidalcea sparsiflora (Southern Checkerbloom). These species are in the same plant family as hibiscus and cacao (the plant from which chocolate comes).

Zeltnera venusta (Charming Centuary, Gentianaceae), with its crazy corkscrew-shaped anthers and ribbed sepals, was a nice surprise on an open hillside.


I was the most excited to see a couple southern Clarkia species–the only all white flower in the genus, Clarkia epiloboides (Willow-Herb Farewell-to-Spring), and the rare Clarkia delecata (Delicate Farewell-to-Spring).

As their common name suggests, these are some of the last spring flowers to bloom in an area, which makes seeing them a little bittersweet. Luckily, however, I can just move my botanizing north and up in elevation.

My next stop was the Torrey Pines Reserve, just up the coast from San Diego and home of the one of the world’s rarest Pines, Pinus torreyana, a species found only here and on Santa Rosa island (Another place in California named Santa Rosa that is not near the other 3! What’s going on here?).  I managed to forget to photograph the pine trees, as I came for the coastal bluff plant community:

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If you are ever in the San Diego area, I highly recommend making a stop here–it’s San Diego’s version of Point Lobos, for bay area folks familiar with that State Park. I’ve written about coastal bluffs previously on this blog. The south coast’s version of this habitat receives much less rain and fog than the central or north coast, and subsequently has cacti, such as the Opuntia sp in the above photo and the rare Ferocactus viridescens (San Diego Barrel Cactus).


A few more stand outs from this location:

The showy and rare Leptosyne maritima (Sea Dahlia, Asteraceae)


The tiny Linanthus dianthiflorus (Fringed Linanthus, Polemoniaceae)


And the honey-scented Piperia cooperi (Cooper’s Rein Orchid, Orchidaceae)


For my last stop i headed North and inland to Santa Rosa Plateau, an area with unique soils and vernal pools. Oak woodlands and grasslands dominate the landscape. This is still Southwestern California, so even here, cacti are everywhere, even growing out of the grass near a large vernal pool.

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This is the only place in the world where Brodiaea santarosae (Santa Rosa Brodiaea, Themidaceae) is found. This species is told from more common relatives by its small, triangular stamenodes (sterile stamens).


Navarretia prostrata (Pincushionplant, Polemoniaceae) was just beginning to bloom


And finally, I found a couple species of one of my favorite genera, Downingia cuspida (Toothed Calicoflower, Campanulaceae) Downingia bella (Beautiful Calicoflower).

The San Joaquin Valley

The San Joaquin Valley forms the southern half of California’s vast Central Valley (Sacramento Valley sits to the north, with the San Francisco Bay delta being the dividing line). This area used to be an epic expanse of wildflower meadows and wetlands, but unfortunately, almost all of the wetlands have been drained and the meadows invaded by European annual grasses. I spent the weekend traveling to both sides of the valley–the foothills of the Greenhorn Mountains to the East and the Carrizo Plain to the West–in search of remnants of San Joaquin’s past glory. With the exception of a quick trip into the oak woodlands, I didn’t see a native tree all weekend. But I did find a few flowers. I botanized in Atriplex (Saltbush) Scrub, where plants must deal with salty, basic (high pH soils):

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and I climbed into beautiful Temblor Range (that’s Carrizo Plain in the background) :

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But mostly I hung out in the “grasslands”of the valley floor.

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Yep, a few flowers.

The color of the weekend was yellow–hills were covered in various golden members of the Aster family. Asters have flowers in dense clusters with outer “ray” and inner “disk” flowers. When you think of a sunflower or a daisy flower, you are actually thinking of a whole cluster of flowers. Many of the species look somewhat similar, and the family has its own unique set of terminology to tell them apart. You need too look at things like the phyllaries (green scales on the back of the flower cluster) and the pappus (tuft of hairs on top of the seed). Here are some of the less common asters from the weekend:

Deinandra pallida (Kern Tarweed). This species is common in the hills around Bakersfield, but is pretty much only found in Kern County. It’s just beginning to bloom.


Lasthenia ferrisae (Alkali Goldfields) is a specialist on salty depressions in the Central Valley. You can see the characteristic fused phyllaries in the second picture.

Monolopia congdonii (San Joaquin Woolythreads). This species does not have any ray flowers. Because the primary function of these flowers is to attract pollinators, the loss of them (which has evolved a number of times) generally indicates a self-pollinator.


Leptosyne calliopsidea (Leafy-stemmed Coryopsis, large yellow) and Layia sp (Tidy tips, white and yellow smaller species). I messed this one up. I assumed the Layia was the common Layia platyglossa, but it turns out there are records of the very rare Layia munzii at the exact spot where I took this. You need to look at the shape of the disk flower pappus to tell them apart, and I don’t even have a close-up photo, so this will remain a mystery. I guess it still is a pretty picture though, even with unidentified plants.


The weekend wasn’t all asters, though. Some additional highlights were two species of Jewelflower that were new to me–the pleasant Caulanthus anceps (Lemmon’s Mustard)


And the bizarre Desert Candle (Caulanthus inflatus)

Yes, those two species are in the same genus–they are a little easier to tell apart than the Layias or the Lasthenias of the world. The weird main stem of the desert candle is hollow, so it’s a fun plant to squeeze.

Delphinium recurvatum (Byron Larkspur). A beautiful specialist in Central Valley Atriplex scrub. In this larkspur flower, the petals are actually the white parts in the middle. The sepals, which are green in most plants, are lavender here. The pointy thing in the back is the nectar spur, which contains the reward for visiting bees.

Finally, as mentioned earlier, I did briefly make it out of the valley and into the foothills. I was looking for a monkey flower species that specializes on patches of bare soil around granite outcrops. I came back with two monkeyflower species that specialize on patches of bare soil around granite outcrops! I found Mimulus congdonii (Cogndon’s Monkeyflower and Mimulus pictus (Calico Monkeyflower) hanging out right next to each other.

I was looking for the later species, as it’s both amazingly patterned and really rare, and it didn’t disappoint. But for the record, I think Mr. Joseph Congdon, a prominent 19th century Sierra botanist, has himself a very nice monkeyflower as well.