Claytonia rubra, what is that? pt. II

Hi, all — I’ve decided to switch things up and simply chat with you a bit about a topic that has apparently been the most popular on my blog so far: Claytonia rubra (Howell) Tidestrom. You may find yourself now asking the question, “Claytonia rubra, what is that?” Well, there’s a blog post for that.

IMG_2004

Claytonia rubra photographed while flowering, plants growing abundantly in the Pinyon-Juniper belt on the Modoc Plateau, northern California.

But Claytonia rubra may be more than meets the eye, especially if you’ve been paying close attention to it where it grows in different areas, or if you’ve been so lucky as to see it from across its entire geospatial distribution. Let’s think about this for a minute, considering first the global range of Claytonia rubra.

Untitled

Range map from Flora of North America Treatment by Miller and Chambers (2003).

It is across this wide and ecologically diverse distribution, north to south from British Columbia to near (probably in) Mexico, and west to east from the San Francisco Bay Area to the Black Hills of South Dakota, that the annual Claytonia rubra displays a seriously diverse range of morphologies. Is it phenotypic plasticity? Is it local adaptation? Is it speciation? Is it hybridization? Is it some mix of all of these? Claytonia rubra is a tough cookie to crack!

IMG_2270

Claytonia rubra photographed while flowering on the Modoc Plateau, northern California. Notice the largest leaf blades (outermost in the rosette) are among the first to have emerged in early development — These lay flat on the ground surface (or nearly so)

Starting with identification, something I’ve found to be fairly characteristic of Claytonia rubra is that its older leaves (outermost in the rosette of basal leaves), which often have the largest blades, tend to lay flat on the ground — some close relatives (like certain subspecies of C. perfoliata) do this too, or something like it, so don’t take this for a smoking gun. Furthermore, some races of C. rubra do not have basal rosettes that lay flat, rather they are elevated ever so slightly above the forest floor. Don’t you just love those kinds of dichotomous key breaks? — Is is erect to ascending (sometimes spreading), or ascending to spreading (sometimes erect)?! — Still, if you see something in the mountains of western North America like in the picture below, where the outermost (older) leaves in the basal rosette lay flat, appressed to the ground, you can be fairly confident that you are looking at something that is quite appropriately called Claytonia rubra.

IMG_5856

Vegetative Claytonia rubra photographed at the Tejon Ranch in the Tehachapi Mountains, southern California.

For effect, compare the leaves of Claytonia rubra plants in the above picture with the leaves of the plant in the picture immediately below, C. perfoliata, both of which were photographed at the Tejon Ranch in somewhat close proximity (either side of the same mountain ridge) — see how Claytonia perfoliata (below) tends to elevate its leaves off the ground?

IMG_5868

Vegetative Claytonia perfoliata photographed at the Tejon Ranch in the Tehachapi Mountains, southern California.

The characteristic of Claytonia rubra have low-growing leaves seems pretty useful, until you come across a putative lineage (sometimes in the same mountain range!) that looks like the plant below — these plants have distinctly erect / ascending leaves, although the proximal portion of their petioles are still appressed to the ground. This gives the leaves a sort of ‘S-curved’ look. Believe it or not, these are another subspecies of Claytonia rubra!

IMG_7912

Claytonia rubra photographed while flowering at the Tejon Ranch in the Tehachapi Mountains, southern California.

This is a time where it comes in handy to know a few other characters that, when used in combination, can help to distinguish Claytonia rubra from similar-looking miner’s lettuce.

IMG_7434

Classic, beet-colored (reddish to purplish) undersides of basal leaves of Claytonia rubra. Whenever possible, try to observe this character in multiple plants — Generally, the basal leaves should be deep green adaxially and reddish abaxially in Claytonia rubra.

For example, the plants photographed above demonstrate another conspicuous characteristic of most lineages of Claytonia rubra — betalain pigmentation is generally evident on the abaxial (lower) surfaces of the basal (and sometimes cauline) leaves, giving them a purple/reddish appearance. This is a sort of ‘no-brainer’ character I tend to point people towards, but just as with the characteristic basal leaf orientation I mentioned above, this morphological character doesn’t always hold true. Plants love exceptions WAY MORE than rules: in this particular case there appears to be an environmental element to variation in Claytonia betalain pigmentation, as evidenced by some unpublished observations I have made in common garden experiments involving C. perfoliata, C. rubra, and some perennials in the C. “peirsonii” complex.

2013-04-28 11.41.08

Variegation on foliage characteristic of some lineages of Claytonia rubra.

OK, so the leaves are sort of laying flat, and kinda red undeneath, but you’re still not totally convinced you are looking at Claytonia rubra and not some other similar-looking miner’s lettuce. Well, you’re in luck — I’ve noticed that many races of Claytonia rubra tend to have the look of variegated leaves, possibly related to a breaking up of the cuticle during development. If you see something like the plant in the picture(s) above, where there are variegated streaks on the leaves of a Claytonia, it is VERY likely that you are indeed looking at Claytonia rubra.

2013-04-28 11.34.01

[From left to right, Claytonia parviflora, C. perfoliata, and C. rubra!] Multiple miner’s lettuce species growing in sympatry in Mill Creek Canyon, San Bernardino Mountains, California.

IF you still can’t be sure about which Claytonia you are looking at — just ask me! That’s what I am here for…

Advertisements

Hybridization — are generalist pollinators the key to success?

I’ve been on a bit of a rant lately concerning hybridization in plant species complexes, which recently resulted in my last post suggesting hybridization could be a potential ‘solution’ to the problem of an ever-changing climate. I want to dig a little deeper now and ask the questions — can generalist pollinators have anything to do with the maintenance of a generalized floral form in Claytonia? If so, can this indirectly act as a selective force for increased hybridization among distantly (and closely) related species? If you have seen the ‘face shots’ from a recent ‘Spring Beauty Pageant‘ than you know what I’m talking about. Maybe you’ve even suggested to a friend, because Claytonia grow like weeds where you are from, that you believe there to be little variation in floral form among species in the genus. I’d agree with you, to a certain extent… but then again, maybe there is so much intra-population variation in floral morphology (coloration, petal shape) that we are blind to see the true pattern of differentiation in floral form among closely related taxa. I’ve touched upon the subject of within-population variation of the flowers of one member of the C. “peirsonii” complex from the southern Sierra Nevada, but now I want to expand on this subject with photographs taken within a single population of C. lanceolata sensu lato on the Great Continental Divide in Montana. As you can easily tell from the first picture below, in which all of the white spots are Claytonia flowers, it is not difficult to conduct this sort of ‘experiment’ yourself. In other words, it is easy to get a lot of face-on photographs of Claytonia flowers because they occur in extremely dense populations. This spring, try to see how much your favorite Claytonia varies in its floral form — you may be surprised at what you find!IMG_8497IMG_8570IMG_8449IMG_8582 IMG_8453IMG_8458IMG_8477IMG_8478IMG_8531IMG_8547IMG_8516     Keep in mind that all of the above pictures are of plants that occur in a single population of C. lanceolata sensu lato on the Great Continental Divide in Montana. As evidenced by the last photograph, even merosity can go haywire from time to time. If I showed you just that last picture, you might even confuse the plants for Lewisia. That is a lot of variation! Are these hybrid plants of C. lanceolata (which has retuse petal apices) crossed with another species in the area with entire petals? Good question! Let me get back to you on that one…

All I know is that multiple Claytonia species can occur in sympatry, and intermediate forms can be found in those areas. This is especially true of the annual species of Claytonia. I haven’t observed putative hybrids among the annuals (i.e., the miner’s lettuces) and tuberous perennials (i.e., C. lanceolata species complex), although I have observed them sharing pollinators in southern California. Pictured below are soft-wing flower beetles (Melyridae) visiting both C. rubra (section Limnia, first picture below) and C. “peirsonii (section Claytonia, second picture below) at the same location on the same day in the southern Sierra Nevada, California. You might remember from one of my very first posts: these pollen eaters are quite effective pollinators.

IMG_5457 IMG_5402Too many questions for a single dissertation to address, but I’ll see what I can do! 😉

Hybridization — problems, or solutions?

IMG_7815

Claytonia perfoliata species complex on the Tejon Ranch — this is only the beginning of your Montiaceae-related nightmares…

The taxonomy for the annual species of Claytonia (section Limnia) is VERY difficult to work with, mostly because diagnostic characters are not well preserved on herbarium specimens. Unfortunately, a molecular phylogeny that spells out the relationships among taxa in this group is still lacking, but I have added many samples as out-group taxa for my own dissertation studies on section Claytonia (i.e., the tuberous perennial Claytonia)… Is the cause for confusion in field identification due to phenotypic plasticity, hybridization, or both? Is it something else altogether, such as the rapid formation of localized ‘races’ due to poor dispersal capabilities? If the difficulty of accurate field identification is due to hybridization, is this a problem? For taxonomy, the morphological consequences of hybridization are an issue that must be addressed, but for the longevity of lineages, hybridization is probably not a ‘problem’ but rather a solution — it might just be the key to sustaining genetic diversity and promoting adaptation in a forever changing climate — evolutionary success! Before I get too deep into the hole I am digging, we’d better take a look at some nice plant images to really smell what I am stepping in 😉

IMG_7887

Claytonia parviflora subsp. viridis — Tejon Ranch. Note the linear basal and cauline leaves of this mildly succulent annual. Were you to collect, you could rest easy with ID of this plant.

IMG_7876

Claytonia parviflora subsp. viridis X C. rubra ?!?!– Tejon Ranch. Note the non-linear basal and cauline leaves of this moderately succulent annual, and the floral morphology of C. rubra. Yet, this plant retains the fully separate leaf pair of C. parviflora subsp. viridis.

Claytonia parviflora subsp. viridis X C. perfoliata ?!?! -- Tejon Ranch. Note the non-linear basal and cauline leaves of this mildly succulent annual.

Claytonia parviflora subsp. viridis X C. perfoliata ?!?! — Tejon Ranch. Note the spatulate basal leaves. I certainly wouldn’t want to be doing a flora of this area, as I’m sure this isn’t the only group with these kinds of ‘problems’ with hybridization 😉

IMG_5921

Claytonia exigua (left) and C. exigua X C. perfoliata (right) ?!?! — Tejon Ranch. Note the glaucus basal leaves of the plant on the right, which should otherwise look like the plant in the first picture of this post. Yikes!

IMG_5880

More fun with sympatry on Tejon Ranch!!! Left to right, Claytonia exigua, a diminutive C. perfoliata, and something that approaches C. rubra in morphology — section Limnia is tough!

IMG_7819

Could this possibly even be the same as any taxon we’ve seen elsewhere in this blog post? I’m really not sure, but I would lean toward calling it C. perfoliata-like. The C. perfoliata complex, including also C. rubra and C. parviflora, is probably the most difficult group in section Limnia.

IMG_5977

This is also Claytonia perfoliata! Its first leaves are narrow like these. Under drought conditions it can ‘bypass’ switching to the more mature spatulate leaf condition by going directly into flowering and therefore only producing the perfoliate cauline leaves.

IMG_5856

Contrast (or compare, in case of my suggested hybrids) the above pictures with this one of Claytonia rubra — this appears to be a good example of this species which at one point was treated as C. perfoliata but has been found to be a unique lineage and is treated as such.

IMG_7912

Now, compare the picture immediately above (of Claytonia rubra subsp. rubra) with this one — same or different?! Same! Well, sorta… This is ALSO C. rubra, presumably subsp. depressa, which apparently also occurs on the Tejon Ranch — how exciting!

Okay, so interestingly enough, I took all of these photos (and many, many, many more) in only one day on Tejon Ranch with Nick Jensen, a colleague at Rancho Santa Ana Botanic Garden doing a floristic study of the area. His website can be found here. This is a fascinating area because it serves (or, served) as a biogeographic traffic signal for the Sierra Nevada, the Transverse Ranges AND the San Joaquin Valley and the Mojave Desert. I suspect the evidence for hybridization exhibited by the numerous sympatric Claytonia here is mirrored in other plant groups on the Tejon Ranch where multiple taxa co-occur.

But that isn’t all, of course — the evidence of hybridization reappears in every mountain range I have explored in southern California! It seems to be a battle among divergent lineages to survive and compete for overlapping and limited niche space near the southern part of the geographic distribution of these plants, but maybe a little cooperation wouldn’t hurt for the ‘greater good’ of Claytonia if it increases genetic diversity… In the San Bernardino Mountains, you can find members of the C. perfoliata species complex in sympatry. The evidence for hybridization in this area mirrors what I observed at Tejon Ranch.

2013-04-28 11.34.01

From left to right, Claytonia parviflora, C. perfoliata and C. rubra, all members of the C. perfoliata species complex occurring together in Mill Creek Canyon, San Bernardino Mountains.

2013-04-28 10.26.07

A good example of Claytonia parviflora; note the erect, linear basal leaves that are almost terete in shape, and the cleft in the disc-like cauline leaf-pair resulting from incomplete fusion of two leaves.

2013-04-28 10.30.53

Compared with the picture immediately above, this one looks like a fusion of C. parviflora and presumably one (or both?) of the other two annual species in the area. I tend to think C. perfoliata may have played a role in the formation of this hybrid, but we can only be sure by DNA sequencing or by extensive cytological screening. Note the erect basal leaves that are no longer linear in shape but instead have rather distinct blades — this is NOT C. parviflora in the strictest sense of the name.

In the San Jacinto Mountains, you can find more of the same — members of the C. perfoliata species complex in sympatry and evidence for hybridization that may make you want to tear your hair out if you are working to identify plant specimens collected here. For instance, the pictures below from the San Jacinto Mountains are more or less taken from within ~1 contiguous square mile in Garner Valley.

IMG_6158

An excellent example of C. parviflora subsp. viridis is strutting its stuff roadside in the San Jacinto Mountains. Here, you have more action in the ring coming from the C. parviflora corner than from elsewhere in the C. perfoliata complex — I’m not sure the reason but think it is related to the locality I visited, a recently burned area in Garner Valley with little overstory cover.

IMG_6046

Compare the picture immediately above (of C. parviflora subsp. viridis) with this one of C. parviflora subsp. parviflora — similarly erect basal leaves that approach a terete-linear shape, but a contrastingly perfoliate cauline leaf-pair that is almost completely fused (as opposed to the free cauline leaves of C. parviflora subsp. viridis photographed above). The two appear to have different coloration under the same conditions here as well in both the flowers and foliage. — Garner Valley, San Jacinto Mountains.

IMG_6067

Now, compare the picture immediately above (of C. parviflora subsp. parviflora) with this one of some sort of C. parviflora hybrid — similarly erect basal leaves but these appear to be forming distinct blade and petiolar regions unlike the other two photos above from the same general location… tempting to call them the same, but I imagine this fishiness has both rhyme and reason to it. — Garner Valley, San Jacinto Mountains.

IMG_6161

This plant is OBVIOUSLY different from the rest, but what do you call it?! Under some Jeffrey pines that survived the fire, these plants approach the morphology of C. perfoliata subsp. mexicana but the smaller leaves in the center of the rosette are suggestive of certain races of C. rubra. — Garner Valley, San Jacinto Mountains.

What a wild and wacky world we live in! Claytonia will keep me busy (and happy) for many years to come…

Is it Spring (Beauty) time already?! pt. II

After 3 more weeks of growth (and more seeds germinating), mature leaves are starting to emerge on some of the annual Claytonia that have germinated from my collections around California in 2013. Cauline leaf morphology is often the most diagnostic character for these taxa, so it is REALLY cool for me to observe these plants through their stages of development!

2013-12-24 15.10.03These annual taxa are well known for hybridization and polyploidy, and it has been suggested that many species complexes are morphologically variable and phenotypically plastic due to these processes, but these plants exhibit quite a bit of ontogenetic variability in leaf morphology in addition to plasticity. Take the Claytonia perfoliata (left) and C. perfoliata X parviflora hybrids (right) below: they still have strap-shaped leaves for the first few whorls, then they will both transition to different versions of ‘spoon-shaped’ and ultimately different degrees of fusion of the cauline leaf pair!

2013-12-24 15.02.08This Claytonia rubra (below) will ultimately look very similar the C. perfoliata x parviflora hybrids (above) in leaf morphology, but in contrast it will have beet red coloration on the abaxial (bottom) surfaces of its leaves.

2013-12-24 15.05.03Being able to identify the various stages of development for any Claytonia collection is imperative for identification–many of these annual taxa can only be distinguished from one another when at flowering maturity, albeit using their leaves!

2013-12-24 15.09.07The Claytonia gypsophiloides seedlings (above) will retain a rather linear leaf morphology of the basal-most leaves through flowering, but as internodes elongate and cauline leaves become more spread apart they will show various degrees of fusion involving leaves of a more lanceolate shape. In addition, these plants will mature to be quite glaucus throughout.

And of course, one cannot forget the ‘ugly duckling’, Claytonia saxosa (below), which is just a bit different from the rest. It will grow to have more oblanceolate-shaped basal leaves with wider cauline leaves that fuse partly at the base. According to a recent survey, Claytonia saxosa is said to be the cutest of all Claytonia!

2013-12-24 15.07.25

Still no sign of the tuberous perennials–I hope it gets cold enough for them to show up to the party!

Is it Spring (Beauty) time already?! pt. I

2013-12-01 11.59.17Turns out that some of the seeds I ‘cast’ into pots this past spring season have germinated over the recent holiday weekend, including some Claytonia saxosa seeds collected from the North Coast Ranges of California. The cotyledons on these plants (pictured above) are a bit unlike the rest of the lot that have germinated in that they are very short and stout, in addition to being deep green in pigmentation. Thus far, all of the other “up and coming” seedlings, including those of C. rubra collected from the San Bernardino Mountains (pictured below), appear to have very elongate cotyledons that are considerably more strap-shaped and light green in pigmentation in comparison to C. saxosa.

2013-12-01 12.10.10In addition, there appears to be some differences among the taxa with more elongate cotyledons, as demonstrated by the C. gypsophiloides seedlings pictured below which seem to stand a bit taller than the rest of the species that have germinated thus far!2013-12-01 12.04.08Compare the cotyledons of C. gypsophiloides (above) with those of some C. perfoliata parviflora hybrids from northern California (below) and you might wonder if you couldn’t identify Claytonia before their first true leaves emerge!

2013-12-01 12.07.44I’ll be interested to see how things develop as we move closer to flowering season for Claytonia! The peculiarities of the C. saxosa seedlings are quite intriguing — I can’t wait for my tuberous perennials to germinate!!!