Frank Landis' Blog

Wet and Wild 1: Willows and Seep Willows

Wow, 3.5 inches of rain in the last two days! Yes, yes, I know anyone outside southern California wouldn’t even bother with an umbrella for that little, but around here, the news media are howling about THE FLOOD. Worse, according to at least one outlet, we environmentalists have caused the flooding (!), because “we” stopped San Diego from pulling on its 1950 tin hardhat and running bulldozers through all the creeks and storm drains so that they’ll drain straight to the ocean. Of course, “THE FLOOD” has occurred where water backed up into the flood plains of the San Diego and Tijuana Rivers, areas that flood during every major wet event, but that doesn’t get much attention. Worse, if all the crap in the storm channels went into the Pacific Ocean, it would trash San Diego’s famous beaches and drive off the tourist. This is the real reason why the city is having trouble implementing this plan, as it runs contrary to the Clean Water Act. But that doesn’t really bubble up to the media surface either. Flooded roads! Drama! Media exposure!

Where was I? Oh yes, there are in fact plants growing inside the flood channels despite the glowers of the SD Storm Water Department, and they are the topic for this entry. The plants? Willows and seep willows, two plants that grow great together. Both of them like water, whether it’s in seasonally flooded arroyos or on the shores of rivers and lakes. Or in the city’s undeveloped canyon bottoms.

To start with, “seep willow” is an alternate name for mulefat, and it isn’t a willow. Instead, Baccharis salicifolia is one of the biggest Asteraceae in California. It’s often mistaken for a true willow (genus Salix), but the white Baccharis composite flowers usually give it away. Mulefat blooms in fall, but the dead flowers and buds are around most of the year. The smell is distinctive too, resinous and easier to remember than describe.

As for telling the true willows apart, that’s a bit harder. My favorite system for southern California is still the one Tom Chester published a few years ago. Go to that site to learn the five willows that are common in San Diego. Actually, there’s only three that are common (four in the desert), so they are not hard to learn.

Why do willows and mulefat look so much alike? The reason is convergent evolution, which is a technical way of saying that living anywhere that can flood is a bit dangerous, and very different species have figured out the same formula for surviving a flash flood. If you’re a plant, you don’t get to run away from danger, and where it floods, you’ve got to deal with surges of water, along with the gravel, rocks, and other debris that come with the water. Both willows and mulefat have worked out a strategy that includes being able to resprout from a stump or branch (useful if a branch gets broken off and carried downstream), having very flexible branches, and long, streamlined leaves. It’s fun to play with the branches of willows and mulefat. They flex all over the place, and both are useful for basketry (think wicker) because of this. These are plants that bend before the water rather than breaking, and if they do break, they can resprout if the flood leaves them in suitable soil. This last property is beloved by restorationists, who propagate these plants from cuttings, because they will grow rapidly and keep banks from eroding.

Sexually, willows and mulefat are also similar. Mulefat blooms in the late fall, willow blooms in winter, and both species have fuzzy seeds that float on the breeze. This is probably convergence again: releasing seeds during flood season is a way to colonize sandbars and other areas scoured bare by floods. I still can’t explain why both mulefat and willows have separate male and female plants, but they do. The easy way to spot the females is to look for unreleased seeds and the resulting fuzz, and it’s easier with mulefat than with willows. The fact that each plant is a single sex can be a problem for restorationists, as they need to plant both male and female plants to insure that they will have breeding partners. It’s a minor but important detail.

Finally, if you look around, you will find mulefat away from the seasonally flooded arroyos it prefers. Often it has been planted, but still, it is common to find mulefat in areas that seldom, if ever, flood. What is it doing there? The simple answer is it’s growing. Happily. The thing to remember is that the mulefat is adapted to surviving floods, but it doesn’t particularly need floods to survive. If there’s a bit of water in the soil, mulefat can happily grow with other dryland Baccharis species (such as coyotebrush or broom baccharis). However, if the site floods, I’d bet that mulefat would be the only survivor. Everyday living isn’t an emergency, despite what the Storm Water Department might want us to believe.


Kissing under the Mistletoe

Why do we kiss under the mistletoe anyway? Following the normal procedure (Googling) I read a bit and found a reference to it being a symbol of peace in Scandinavia, linking it to the legend of Baldur’s death. And then there’s the obligatory reference to druid’s cutting down mistletoe from a mistle-oak on the SUMMER solstice with a golden sickle, and…

Right. Actually, all you have to do is actually look at a fruiting mistletoe to realize the answer is a lot more graphic. But I’ll get to that in a bit. Since mistletoes were one of my late grandmother’s favorite plants and it is the season for harvesting the darlings, I thought I’d add a bit to the mistletoe lore.

To us botanists, mistletoes are a group of hemi-parasitic plants in the order Santalales. Yes, Santa has something to do with mistletoe…not really. To unpack that statement: a parasite is something that gains nutrients from a host, to the host’s detriment. Parasites come in two flavors: holo-parasites that get everything from its host, and hemi-parasites that get some of its nutrients from outside their hosts. Parasites don’t generally read, so reality is a lot more messy than that, as anyone who hosts a financial holoparasite knows. But I digress. The order Santalales has nothing to do with Santa either, sadly. It is named after the sandalwood genus Santalum. American mistletoes used to be in their own family, Viscaceae, but if you follow the current APG system, they are also grouped in the Santalaceae. So if you can think of Santa smelling like sandalwood and holding a mistletoe, then you’ve got something to remember this whole group by.

According to the San Diego Plant Atlas, San Diego County hosts two genera and nine species of mistletoes, none of which are the European mistletoe (Viscum album) of legend, lore, and Victorian-era coverups. The two genera are Arceuthobium and Phoradendron. Despite what I just said, Arceuthobiums, commonly known as dwarf mistletoes, are holoparasites. How do you tell? They’re not green. Hemiparasitic mistletoes are green and photosynthesize. Dwarf mistletoes attack conifers, and you can identify them based on the identity of the host tree. Phoradendron mistletoes are green, and of the seven species, the ones you tend to see in the city’s canyons are P. macrophyllum on sycamores among other non-oak trees, and P. villosum primarily on oaks. Winter is a great time to look for mistletoes, especially in the sycamores, because there aren’t any leaves to block your view of the mistletoes in the crowns.

So let’s get folkloric. You can read all about the druids and the Norse elsewhere (see link above). All of these people seem to repeat the same stuff from the old stories, so I’ll add a couple more tidbits. For instance, the symbolism of cutting mistletoe from an oak with a golden sickle at mid-summer. As explained by a modern druid, the sickle is a moon symbol, gold is for the sun, the mistletoe is a weird plant that grows in the air (spirit) not the ground (reality), the summer solstice is the time of maximum daylight, after which the daylight decreases, and English mistletoe rarely grows on oaks, so finding one on an oak is a rare event. All nice and symbolic, except that the druids probably used a falx, which is more like a bill-hook. Another modern druid actually made a couple of golden sickles out of 9 carat gold and found that yes, you can cut mistletoe with it. You get about two sprigs before the golden blade breaks. Feel free to replicate the experiment. I can tell you from experience that local mistletoe wood is quite brittle.

But kissing under the mistletoe… Yes, yes. It’s a pretty poisonous plant, but we’ll ignore that. That’s not why you stick it up. Look instead at mistletoe biology. Mistletoe berries are spread by birds that eat the berries. To help the seeds get crapped out on branches rather than the ground, mistletoe berries are very sticky. Birds wipe their butts on branches to get them out, and voila! the seed has a new host to grow into. So we’re talking about a seed that’s off-white, like a little pearl of something sticky, and it rather resembles some other droplet that’s off-white and rather sticky. You can start thinking about sexual symbolism here. In the old days, boys used to pull a berry off the mistletoe each time they kissed a girl under it, too. They may have been counting uses, or they may have been hoping for something else after the kiss. Hard to tell.

And if you look at the fruiting branch of a mistletoe, you’ll see that it’s a rather stiff, upright little branch that’s quite thick in proportion to its height. The berries are paired on either side of it, and typically, the last two berries are the one at the base of the nice straight bare stem. Yes, it’s about the most blatantly phallic symbol you can find in the local flora, and we’re really talking about a little fertility ritual here. So ignore the hemi-parasitism, ignore the Santa order stuff, and ignore the whole story of Baldur. Just have fun smooching under the mistletoe!

Writing update
December 7, 2010, 2:58 pm
Filed under: California Native Plants, NANOWRIMO, Nature Writing, Science Fiction, writing

Hi All,

Ah, the silence of November. It was productive. Here’s what was up:

–I did my third National Novel Writing Month (NANOWRIMO) contest, and for the second year in a row, I finished the necessary 50,000 words. Since I started late and had a lot of other things going on, when I was writing, I wrote a lot. This is the start of another science fiction novel, one about time travel and conservation.

–The result of my NANOWRIMO 2009, Scion of the Zodiac is going up for publication. While I’m still shopping it around to see if any publishers want it, I decided to publish it myself and see if anyone liked it. It’s currently available at Smashwords and Lulu. Hopefully before Christmas it will be available at Mysterious Galaxy bookstore as well. The basic idea is that, if a publisher wants to option it, I’ll simply take down the current self-published versions and let them publish it.

Bottom line is: if you want to read science fiction with a large dose of ecology in it, check it out. I’ll post links as I get them.

–The next writing item on my list are those promised blog entries about native plants, to help Mike and anyone else for leading public hikes in the spring. If you have any preferences for topics, let me know.