Saturday, March 26, 2016

Malibu Creek Wanderings

Greater periwinkle, Vinca major.
Today I had a few targets in mind. My first goal was to check a section of the Backbone Trail running through riparian, where someone had recently reported a nemesis species of mine, American yellowrocket, a fairly uncommon species here that only grows in certain damp, shady locations near creeks. Fortunately that was also fairly close to the Tapia Spur trail at Malibu Creek State Park, where the cool Cithara buckwheat is said to grow. I had never visited either of these two spots before so I knew there was going to a lot of cool habitat to look forward to!

Beside the car I noted the unfortunately ubiquitous greater periwinkle, a nice looking garden plant but one that rapidly spreads and infests riparian habitats. This was though the first time I've seen them in flower. One patch was covered in a a powdery white mildew, which I determined is almost definitely Golovinomyces orontii, a species specific to this plant. A great start to the day was seeing black cottonwood growing in the valley along Piuma Road, where this portion of the Backbone Trail begins. The leaves of these trees are much darker than other cottonwoods, hence the vernacular, and it is a very localized species in the Santa Monicas. The western spotless ladybug (Cycloneda polita) was actually quite common here, and this was the first time I had seen adults. I sweep-netted the larva of this native species in my neighbourhood several years back. In our area it has a very erratic and uncommon distribution, although it is quite common further north.

Golovinomyces orontii on Vinca major.
Black cottonwood, Populus trichocarpa.

At one point the trail disappears and turns into a car park for the California Wildlife Center! It took me a few moments to find the continuation, but as soon as I did, I was greeted with the yellow flowers of the native mustard, American yellowrocket. Success! On nearby California ash I scoped out some unfamiliar lichens, and with some outside help was able to identify one as a very likely candidate for Lecanora circumborealis. thanks to the substrate (bark) and black apothecia. The common name of this lichen is usually black-eyed rim lichen, and indeed it is one of the few species in the genus with dark apothecia.

American yellowrocket, Barbarea ootheceras.
Lecanora circumborealis on Fraxinus dipetala.
I continued a little further up the path to see what was about, and I bumped into two sprigs of silver wattle, Acacia dealbata. Apparently this is a known establishment of this Australian tree which the NPS have tried time and time again to eradicate. Some of the feathery leaves were infected by armoured scale insects in the family Diaspididae. If only it were possible to identify those!

Silver wattle, Acacia dealbata.
Thoroughly aware of time, I headed back and along Piuma Road, on route to the Tapia Spur trail. On the way I found Cretan mallow, one of a few similar non-native species, but distinctive in seed morphology as well as the very large flowers and upright growth.

Cretan mallow, Malva pseudolavatera.
On Tapia Spur itself, once I found the right timing to sneak past the entry rangers  (just kidding!), I stumbled across a darkling beetle that I had been seeking for a while, Coelocnemis magna. Unlike the more common Eleodes the beetles in this genus have golden hairs under the legs, and are a little stouter in proportions overall.

Coelocnemis magna.
The golden hairs of Coleocnemis magna.
Unfortunately I could not find the Cithara buckwheat, but the rocky talus slopes along the trail were interesting. On one corner I found lesser chickweed, a nondescript green plant that gave me a lot of hassle when it came to identification. These plants were as "in flower" as they were going to get, with no visible petals or anything you'd associate with a flower at all. I heard a field cricket singing nearby and picked apart the rocks until it jumped out. With a recording and images in hand I dropped an email by David Weissman who confirmed this was the undescribed species Gryllus sp. "rock chirper". As cool as it was finding a species effectively new to science it is not actually that rare in California. Before finding this cricket though I unearthed some terrifyingly large spiders that jumped out and skittered away with amazing speed. These spiders were eerily reminiscent of the good ol' hunstman spiders from Australia; lo and behold Curicaberis peninsulans is more than just reminiscent of those nightmarish creatures, it is one!

Lesser chickweed, Stellaria pallida, bearing the most flowery
looking flowers you can expect to find in this species! Note that the
green "petals" are actually sepals, the part of a flower that supports the
petals...if it had any!
Undescribed Gryllus sp. "rock chirper"

The terror that is Curicaberis peninsulans!