The Fantastic Four, Online Friends and Hemiparasites

Wow. What a great weekend. First, because we rode the Fantastic Four, which is how I will from hereon refer to the absolute 4 best mountain bike rides of the greater Hurricane-St. George quasi-rura-burba-politan area. They are- in order of utter awesomeness- Little Creek, Gooseberry, Zen and Guacamole.

Second, because I finally met, and rode with, KanyonKris.

This Part Seems Like A Tangent But Isn’t

For several years my brother- let’s call him “Phil”- lived in NYC. Phil has always been really into music, repeatedly deep-ending into various bands that apparently were just about to be as Big As The Beatles, but never did, invariably because of some tragic mishap, contract snafu, break-up or overdose, which usually occurred sometime back in the late 70’s/early 80’s. Examples include Television, Denim, Big Dipper, Undertones, Luna, Big Star, and any band that ever had Peter Holsapple as a member*.

*Except REM. Too successful.

Phil spent an inordinate amount of time and effort researching these bands, and corresponding online with other diehard fans of these bands, befriending several of them, and on multiple occasions, meeting them, (usually at some gig reuniting the surviving members of the band in question.) The results of these meetings- which were dutifully related to our sister- let’s call her “Elizabeth”- and me by Phil’s wife- let’s call her “Dara”- were predictably rich: Phil’s Online Friend would always turn out in person to be, well… a few tracks short of an EP. Yes, Phil met some odd ducks online, for which Elizabeth and I delighted in teasing him on countless occasions.

Now, fast forward nearly a decade. I have a blog. One of the regular readers, who also has a blog, is a frequent commenter. We have many similar interests, including science, the outdoors, and mountain-biking. He lives only 40 miles away, and coincidentally plans to be in St. George the same weekend as me. So naturally, we make plans to meet and ride together.

So Saturday morning, as I waited for KanyonKris to pull up to the motel lot* to meet us, my over-riding thought was: Please, please, don’t let this guy be a whack-job, or Phil will never ever let me hear the end of it.

*Yes, the abysmal Friday night weather drove even me- Ultimate Diehard Camper- to seek refuge in a motel. But camping Saturday night was great.

All About KanyonKris

I needn’t have worried. KanyonKris is one of the friendliest, most-likable, well-adjusted* guys I’ve ever met. My friends instantly liked him, and together we had fantastic day. He’s also the first mtn biker I met who’s actually done my mountain-lion safety eyes. (pic left) What a guy! We had a fun quick ride on Guacamole in the morning, then headed over to Little Creek in the afternoon.

*Certainly he’s more well-adjusted, friendly and likable than I am. Seriously, he’s a great guy. If you don’t know either of us in real life, but ever have an opportunity to meet one or the other, pick Kris. I would.

Side Note: KK’s wife- let’s call her “Jolene”- met up with us for the Little Creek ride. She of course is equally wonderful and instantly likable, and is a tough biker, riding all over the Mesa with us at a fine clip, having already raced that morning. (We were all very impressed, as whenever any of us races, the only follow-on activities we engage in are sitting around, drinking beer, and either a) bragging about or b) making excuses for, our race performance.)

Not only is KanyonKris a great guy, but he and Jolene have the Koolest* life. They live down in Utah Valley- an hour closer to St. George than I do- and Kris has a brother in St. George with whom they can stay whenever they feel like it. And Jolene’s parents, who live in the town next to them, watch their kids pretty much whenever. Biking Wife, No-Cost Reliable Childcare, Strategically-Located Sibling. A Kool Kombination*.

*Sorry. I kould not resist.

Longtime readers know that Little Creek is pretty much my favorite place in the world and it was fun to show Kris and Jolene around so many of the places up there I’ve blogged about, including the relic Ponderosas, North-facing mossy walls and big bright patches of Elegant Sunburst Lichen.

Wherever we rode over the weekend, hints of Spring were all around, and although we were still ~2 weeks early for desert wildflowers, everything’s teed up and getting ready to bloom. The Blackbrush is nearly fully-leafed out, and up on the mesas the Serviceberry is covered with soft, juvenile, light-green leaflets. And the Manzanita was already bristling with delicate pink blossoms. (pic right)

Saturday night we camped up on Little Creek, and as is my habit, I slept out under the stars. One of the reasons I like sleeping out (and not in a tent) is that when you wake up, you’re already outside; you don’t have to hem and haw and screw up your courage to brave the cold and crawl outside and see the dawn- you’re already in it. (pic left= dawn view E from camp) And so a few minutes before sunrise, while OC Rick, Clean Colin and Aurora Coryalis dozed in their respective tents*, I wandered about the mesa rim, snapping photos and checking out plants.

*Yes, they each bring their own tent each about 20 feet apart, and I go off another 20-30 feet or so to roll out my pad & bag. Our campsites are like little suburban subdivisions, each of us with our own “yard”.

I poked around at various mosses, lichens, cacti, and shrubs, (pic right = dawn view NW from camp) but my attention was most drawn to this common plant: Juniper Mistletoe, Phoradendron juniperinum. Though I’ve seen plenty of Mistletoe on Juniper before, there was something I noticed this time that really bugged me. As the day progressed and we spent several hours riding on nearby Gooseberry Mesa, it continued to bug me, and I chewed on it intermittently on the drive home. But first, a bit about Mistletoe.

I mentioned Phoradendron in a side note to a post I did on Dwarf Mistletoe, Arceuthobium, back in February. It’s a genus of roughly 3 dozen species native to the Western hemisphere. Like Dwarf Mistletoe, it’s parasitic, using one of a number of different conifers or angiosperm trees as its host. Juniper Mistletoe targets a couple of different Junipers, including our old friend- and my alternative nominee for Utah State Tree- Utah Juniper, Juniperus osteosperma.

Its form is that of a clump of “needles” on a Juniper that doesn’t look quite right. They’re much denser than a typical branch of twigs, and the color is slightly off, usually a tinge yellower, or sometimes even brown (when it dies) next to the grayer-green of the surrounding branches. And if you pause for a moment and look closely, you’ll see it isn’t actually part of the tree at all, but rather something completely different: another plant growing out of the wood of the Juniper.

All About Hemiparasites

Up till now when talking about Mistletoes and Dwarf Mistletoes, I’ve been pretty careless about throwing the term “parasite” around; it’s time to clean up my language. Technically, Phoradendron is a hemiparasite, in that it obtains water and nutrients from its host (with no benefit to the host) but also photosynthesizes (some of) its own nutrients. Hemiparasites are fascinating because they’re sorta-kinda parasites, and one wonders if they’ve evolved “half-way” towards parasitism (or maybe even “half-way back”.) But they’re definitely more than a simple epiphyte; Juniper Mistletoe can kill individual limbs and even whole trees, though it rarely seems to damage whole stands of Juniper on a large scale.

Side note: This actually wasn’t the only, or even first, hemiparasite I saw this past weekend. Desert Paintbrush, Castilleja chromosa, (pic right) which is already starting to bloom down on Zen trail, is also hemiparasitic, commonly attaching to the roots of Blackbrush, Sagebrush and other shrubs. But since oncoming weather prevented us from lingering, and since Paintbrushes will be plenty common in another 3 months in the Wasatch, I’ll save them for another post.

There are plants that are “full” or holoparasites, and which don’t photosynthesize at all. An example would be Dodder* (genus = Cuscuta, ~170 different species) (pic left) a shrubby, hairy-looking parasite, species of which come in various shades of yellow, orange or red.

*Some Dodder species actually do contain low levels of apparently functional chlorophyll, technically making them hemiparasitic.

Tangent: Supposedly there are very rare albino Coast Redwoods which are root-clones of a “normal” Redwood. These albinos, which never grow very tall, are actually holoparasites of their clonal parent. Locations of such albino Redwoods are allegedly kept secret to discourage visitation.

P. juniperus is spread from tree to tree not by exploding seedpods (like Dwarf Mistletoe) but by birds, most commonly Thrushes, Robins and Solitaires, who eat the berries and then pass the seeds while perched on a nearby, different, Juniper.

Tangent: So there’s something cool going on here. Longtime readers may remember that what looks like a berry on a Juniper is not actually a berry, but rather a modified cone which is can be thought of as an alternate evolutionary path toward “fruit-hood”. But the berries on Juniper Mistletoe are true, anatomically correct berries (Phoradendron is an angiosperm, as we’ll discuss in a moment) so the Juniper Mistletoe berries are real, actual berries, on a Juniper tree.

So this is all well and good, but I knew all this before this past weekend. What was bugging me was something else: Why does Juniper Mistletoe look so much like Juniper?

Only 3 possible reasons occurred to me. First, 2 different plant species often look alike if they’re closely-related. We can rule that one right out; Juniper is a conifer, Mistletoe is an angiosperm. They haven’t shared a common ancestor for at least a couple hundred million years.

Tangent: For a long time it was believed that there was no such thing as a parasitic conifer. Then one was found- Parasitaxus ustus, (pic right)a small woody shrub which is actually a Podocarp, is an honest-to-goodness coniferous parasite, with only vestigial, non-functional chloroplasts. It’s native to- yes, where else- my favorite Gondwanaland-fragment and conifer wonderland, New Caledonia. (Man, I have got to get my ass down there sometime. That place sounds amazing.)

The second possible reason would be that both Juniper and Juniper Mistletoe evolved their common twig-form in response to similar environmental pressures. But this idea too quickly falls apart. There are other angiosperms all over the place up on Little Creek and Gooseberry. Sagebrush, Serviceberry, Tree Cholla, Prickly Pear, Blackbrush, Cliffrose- none of them look anything like a Juniper. The chances that the one angiosperm up there that happened to follow the same evolutionary-morphology path as Juniper being the same one that parasitizes it seems next to zero.

And furthermore, when you get up close, they don’t have the same morphology. (pic left) The Mistletoe stems are scale-less/leafless; the green is the stems themselves, which are photosynthetic. They just look like Juniper twigs from a distance, but up close they’re a mimic- a cheap copy.

That leaves the third possibility, which is that the Mistletoe has evolved to mimic its host. But why? Junipers can’t see, even if they did have some proactive way of removing the Mistletoe. What does it matter what the parasite looks like?

The only possibility I can think of is that host-mimicry enables the Mistletoe to escape detection by some possible predator that would favor eating the stems of the Mistletoe over Juniper twigs. And since the Mistletoe generally occurs higher than a deer or cow can reach, that predator must be some kind of bird or a squirrel of some sort.

Hours later, after I finally arrived home (while I should’ve been sleeping) some poking around online seems to suggest that indeed I figured it out; a number of mistletoes do seem to mimic their hosts, even down to the species level, and it’s assumed that such mimicry is probably a defense against herbivory. Being offline for a weekend, it was fun to figure it out on my own.

Like so many desert trips, this one left me thinking straightaway about the next. But this time my daydreaming has some urgency; peak wildflower bloom is about 3 weeks away. I need to figure out a daytrip strategy down there fast.

Postscript: It occurred to me last night, and may well have occurred to you, that there’s an obvious problem with the mimicry theory: the copy-job sucks. By the end of the day Sunday as we were riding on Gooseberry Mesa I was routinely picking out clumps of P. juniperinum from 40-50 feet away, in part by shape, but largely by the color- just a bit too yellow-green. As I’ve blogged previously, the color vision of pretty much any bird blows mine away; surely they could easily pick out the clumps of Mistletoe?

That leaves me with only 2 possible explanations: First is that the color-match is better when the Mistletoe is very young, and presumably more vulnerable. I have no evidence for this, and would have to do a lot more poking around to pursue this idea. Second is that the mimicry is a primarily a defense against squirrels, who (I believe) lack color vision.