Saturday, April 4, 2015

On the Roadside

It is amazing to me what beauty can be found on the side of a road. So much can be missed if you are the driver, or even as a passenger. Occasionally I see something as I'm driving that begs for a closer inspection, I must investigate. A slight contrast in color, something that resembles a flower I have never seen before, my curiosity gets the better of me and I know I'll regret not looking. Of course, sometimes it really is nothing, but this way I will know.

Invasive weeds

Many common roadside weeds are also interesting in close inspection, though not necessarily good garden plants (bad leaf to flower ratio, too many self-sown seedlings), but are nice in a meadow-lawn (another way of saying I'm perpetually behind in the lawn maintenance). These small plants have a certain charm, though I would never intentionally grow them. Invasive plants are often plants that have followed humans around for ages as we spread ourselves around the continents (being, in fact, invasive species ourselves, though quite naturalized and probably difficult to eradicate at this point).

I imagine most of our most common weeds ended up where they are originally by being mixed up in grain seed, or other agricultural seed, that had then been spread by the help of plants and animals. We humans certainly play a role in their success, as many of them pop up in disturbed soil, and we are very disturbing in that regard. It has long been my belief that the best weed control is a dense layer of other plants, and this has shown to be consistent with my observations. Disturbed soil often has nothing growing on it, thus no competition and a lot of good places for seed to land. This also works against us, especially in the case of the giant blackberry (Rubus armeniacus) plants that grow ten feet tall and smother out anything shorter than a tree.

Another thing that I believe aids in the spread of noxious invaders is their ability to self pollinate or to set seed without the need for pollination (which is the case with the dandelions, hawkweeds and violets), otherwise known as apomixis. Pollinators like bees and flies do however like the flowers of many invaders, which is both good and bad for the same reason. Erodium and Rubus are very attractive to bees and flies in my yard. I am both happy that they can make use of the flowers, especially the Erodium (I'd prefer it over the invasive grasses any day), and torn that they are facilitating the spread of a#&hole plants like the Armenian giant blackberry which refuse to go away, and desecrates shockingly enormous areas of land, and dispels any chance of native plants to survive, let alone succeed! But the berries are better than what you can buy in the store, so I'll sell out a little...


Veronica persica

Geranium molle
Silene latifolia ssp. alba

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Not everything on the side of the road is a weed (at least not a foreign invader), some roadside wildflowers are stunning natives. Bulbs and bulb-like plants are of great interest to me, and I am lucky to be able to observe so many native ones here in the Rogue Valley. Most of the time I am not consciously looking for the flowers, but their presence grasps the attention of my peripheral and I need to stop and look.



Dichelostemma capitatum

Below is a large colony of Dichelostemma capitatum growing on a roadside bank at the bottom of a hill in Rogue River, Oregon, not far from where I live. The flowers of these flowers are small and many people may pass by without notice, but someone like me who is always looking for beauty in the world sees such a community of wildflowers and stops to take pictures! What a nerd!

Dichelostemma, and its close relatives in the Brodiaeoideae (formerly treated as the family Themidaceae, now as a subfamily under the Asparagaceae) are perennial herbs native solely to western North America from southwestern Canada to possibly as far south as Guatemala. They are goephytes which grow from corms, which are swollen underground modified stems which store starch to be used to allow the plants to survive adverse conditions (like drought and hot summers, like what we experience here). Though they are often referred to simply as "bulbs" (like Crocus "bulbs", actually corms), they differ in that true bulbs are made of modified leaves that store energy and nutrients in the form of starch, instead of in a modified swollen stem. Bulbs are most often perennating, while the actual corm of a cormous perennial is replaced every year (the current years corm rots away).

Dichelostemma is a bee pollinated genus, at least that is what I have observed. Small solitary bees work the plants for both pollen and nectar simultaneously, which adds to the time spent at each flower, which results in more contact with the anthers and possibly the stigmatic surfaces. Bee flies (Bombyliidae) also visit the flowers, but I would doubt their effectiveness as pollinators because of the fact that they hover over the flower while their long proboscis probes for nectar, making little contact with the sexual organs. Syrphids will occasionally visit the flowers, but I have observed so few on the flowers that I question their reliance as pollinators (though I wouldn't rule it out).

Dichelostemma capitatum
Dichelostemma capitatum
Dichelostemma capitatum
Dichelostemma capitatum
Dichelostemma capitatum

To my delight, I returned to a patch of roadside wildflowers from a former post to find a few gems! Fritillaria recurva has for a long time been something precious to me. This is however the first year which I have even ever seen the plant in person, and after reading about it and being swooned by photos of the plant, I developed the usual obsession over a plant that only existed in my mind (at the time, anyway). Now that I have seen it and experienced its presence, both at Upper Table Rock and now fifteen minutes from my house at the side of the road, I have only deep reverence for the species.

The flowering plants were around two to two and a half feet tall. Fritillaria's are all perennials that grow from true bulbs, but unlike most true bulbs the actual storage structures are annual. The bulbs of most species consist of two large scales (modified leaves) joined at the base (to the basal plate, the squashed modified true stem). The flowering scape grows up through the center of the scales from the basal plate. In many North American species the bulbs produce many tiny offsets called "rice-grain" bulblets, which can be planted on their own to eventually grow into large plants, clones of the original bulb. This may be an insurance policy in case the main "mother" bulb dies for some reason, or if a disturbance of the soil kills the main plant.

Fritillaria recurva
Fritillaria recurva in habitat with Arbutus menziesii and Toxicodendron diversilobum
Fritillaria recurva in bud

2 comments:

  1. I was looking for pollinators on them, but saw none.

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    Replies
    1. No pollinators in these pictures, the weather has not been in agreeance with the flight capabilities of pollinating insects! Sunny weather with a slight breeze seems to be best. Warmth and a breeze to spread the undetectable fragrance (undetectable to us, anyway) beckons floral visits from foraging insects.

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