Petalidium ohopohense

Oh, Ohopo, oh-no. We need another look at you. You’ve got some pretty pink flowers and even prettier yellow nectar guides, but that doesn’t mean that we fully know your name. World: meet Petalidium complexity. Its sort of like trying to count above 10 as a botanist: difficult. Why not just say “infinity”?

Infinitely difficult to understand until (a) we get some serious molecular data or (b) the plants start speaking English (AND answering our questions).

Wild collected, Namibia, Tripp & Dexter #849 (RSA-POM); Photos by Erin Tripp

Petalidium luteo-album

This is a DAMN fine species and you would be hard pressed to ever find anything so beautiful in the Logee’s catalogue. Petalidium luteo-album is clearly the sister species to P. giessii. It (P. luteo-album) also occurs with the latter (P. giessii) in the Grootberg Mountains (= geological capital of the universe), but also has a much wider range, extending into the northern Kaokoveld. It is also the only species of Petalidium that produces truly succulent leaves.

In May 2014, we found our first ever mixed population of the two species (P. luteo-album and P. giessii). How on Earth do these species maintain reproductive isolation? They were flowering concurrently, and literally doing so side-by-side (see photo of the two, laid against a herbarium blotter). In all fairness, it did seem that the former was going out of flower just as the latter was coming into flower, which is precisely what one would expect under reproductive character displacement scenarios. In any case, the population is georeferenced, and desperately in need of further field (and genetic) study.

Photo with the ruler so clearly shows the genus synapomorphy: paired bracts subtending each flower. That photo also very nicely shows the ribbed (‘herringbone’) patterning on the lower portion of the corolla throat. It doesn’t matter which way you twist the flower around, or whether you look at it while standing on your head. Petalidium luteo-album will forever enchant you. Watch out for the spell.

Wild collected, Namibia, Tripp & Dexter #830 (RSA-POM); Photo by Erin Tripp

Petalidium lucens

Dear Petalidium lucens,

Way back when I was a graduate student at DUKE, I happened upon a loan of a herbarium specimen of you. I remember the day: I was sitting at the far end of the herbarium, with Dr. Wilbur looking over my shoulder to monitor my mischief. When I laid eyes on your bracts, it was love at first sight. (That, and the dense white tomentum of Petalidium englerianum….). At the time, I never knew that you and I would eventually cross paths. Well, 10 years later, we have. I am so glad that you waited for me…..

I have always wanted to tell you that I find you to be among the most brilliant species of what Kyle and I call “the Southern Clade” (Did you know you were part of a clade? Do you care?). Please tell me: what is the developmental basis for those beautiful, papery bracts that are interwoven by thick, red veins? What is the adaptive value, if any? And why is it that you inhabit such a narrow corner of Namibia, refusing to grow anywhere else on Earth?

Locally abundant, globally beautiful, you always make me smile whether in the cellulose, in the herbarium, from a photograph, or via a memory….

With fondness,

A botanical admirer

PS: Your friend, Petalidium linifolium, told me to tell you to get some skinnier leaves.

Wild collected, Namibia, Tripp et al. #2065 (RSA-POM); Photo by Erin Tripp

Petalidium linifolium

Woot woot!

Here we go with the “southern clade”… species of Petalidium that are restricted to southern Namibia (and in some cases, ever so slightly beyond). They have the loveliest of calyces – papery with glowing thick red veins against an otherwise nearly translucent background. Petalidium linifolium is closely related to P. lucens and P. parvifolia. Kyle and I have some further work to do before we make any final calls on this clade, but for now, sit back and enjoy the glory. Maybe with a nice glass of cool, South African chardonnay (I recommend something from Stellenbosch…perhaps a Jordan….served at a perfect 49 degrees F). This species wants you to embrace it properly.

Wild collected, Namibia, Tripp et al. #2031 (RSA-POM); Photo by Erin Tripp

Petalidium lanatum

Kyle and I first saw Petalidium lanatum adjacent to our first living, in-situ Welwitschia, if that tells you anything. Yep — the Namib Desert. Home to some of the most intense sand storms on Earth, and where decades pass without a millimeter of rain. You think you have it bad?

Sister species of (or, err, maybe synonymous with) Petalidium halimoides — check that page out.

For a plant with such a gnarly attitude, it sure has precious, innocent, tiny red flowers. Note the infructescence that has become woody and spiny with age (yes, just like you).

Subsequent photos: I need you to pay close attention to this. Photo was taken just as we entered the true Namib Desert. This plant looks absolutely toasted – DEAD. A skeleton of sorts, like all those ship wrecks on the Atlantic coast of the desert. But: WRONG! You’d be wrong wrong wrong if you guessed it, just as I did. This plant is actually quite alive. perhaps just a leaf or two per branch, but: that counts as ALIVE… and it was even flowering. This species can hold its own with any pirate.

Scope out the tap root: even longer than that of P. halimoides. That thing is decades old, to be sure..

In the last photo you can see it dominating the landscape (as it is wont to do).

Wild collected, Namibia, Tripp & Dexter #879 (RSA-POM); Photo by Erin Tripp

Wild collected, Namibia, Tripp & Dexter #4108 (RSA-POM); Photo by Erin Tripp

Wild collected, Namibia, Tripp & Dexter #4112 (RSA-POM); Photo by Erin Tripp

Petalidium halimoides

I sort of have a thing for this plant. It’s true. Not quite like the Roger Federer thing, but…

I would put up some Vegas chips on hypothesis that this is among the top 100 hardiest species of plants in the world. Well, together with Petalidium lanatum (no doubt its sister species, or maybe I should sink the latter into the former….). Petalidium halimoides is also an opportunist. Above, you see it in several contexts: lush-ish fields and extremely dry, vegetation-less soils of the Namib Desert. Yep – it does it all. Something to aspire to.

First photo: check out the stellate trichomes that you can see with naked eye.

Second photo: check out the Martian taproot.

Third photo: Kyle doing his amazing thing. And note plant abundance. Petalidium halimoides dominates many landscapes, including much of the Kaokoveld.

Fourth photo: Look at those amazing fruiting heads (=infructescences) that the Lucinda McDade-ster is holding (also note her awesome plaid shirt). These fruiting heads become woody and spiny with age… just like the rest of us.

Seed predation is such a huge debacle in ultra-arid deserts that my personal hypothesis is: this ‘head-like’ morphology evolved as a means of protecting most (but not all) of your seed crop. Could be experimentally tested.

In the last photo, have a gander at the super special growth form. Sprawling and with giant head-like inflorescences. Sort of makes you want to just give it a hug.

Wild collected, Namibia, Tripp & Dexter #833,  1990, & 1965 (RSA-POM); Photo by Erin Tripp

Wild collected, Namibia, Tripp, McDade & Dexter #4077 (RSA-POM); Photo by Erin Tripp

Petalidium giessii

Special species!! Sort of like Special Sauce but WAY, way better! Just take my word for it!

First specialness: GROOTBERG MOUNTAINS. I need not say more. Best geology in the world. GO THERE.

Second specialness (competes for first): ACANTHACEAE PRODUCE SWEET FLORAL ODORS IN THE OLD WORLD. It is true – so very true! And I aim to get Rob Raguso and his awesomeness on this, as soon as I am able and have the funding to do so.

I first spotted this species from ~75 meters away, while flying down the (dirt, major) highway. As soon as I opened my door, we were met with a flush of intense, sweet jasmine-like odor. I took one look at a blazing ball of yellowness some distance away from me and knew immediately that (a) it was a Petalidium and (b) it was responsible for that amazing fragrance.

Note to the non-Acanth user community: this family of plants is basically known to be odorless. I was blown away by the discovery.

Petalidum giessii is extremely restricted in its distribution… more or less limited to a ~100 km stretch as far as we can tell. And it is completely distinctive – no doubt that it is a “good” species. Also little doubt that it is a close relative of Petalidium luteo-album, but… I have been wrong before. Once, I think.

First couple of photos: admire the Grootbergs and the plant.

Close-up of the corolla photo: in full glory…. you can practically smell it from your computer.

Yet another photo: in fruit from the previous season… rains hadn’t yet arrived…. photographed shortly before I was attacked by a leopard at dusk. Not kidding. Scar on lower right calf to prove it….

And finally: discover of a new population of this remarkable species, while exiting the depths of the remote Ugab River valley (May 2014, with Essie, Leevi, David, Josephina, and Iain).

Wild collected, Namibia, Tripp & Dexter #825 (RSA-POM); Photo by Erin Tripp

Petalidium englerianum

I haven’t a clue how to convey the coolness of this species to you. Petalidium englerianum was the very first in the genus to capture me (and shortly thereafter, Petalidium lucens — see that page). I saw it in the herbarium. Its leaves were bright white and begging for sunglasses owing to a thick indumentum of stellate trichomes. The species absolutely decorates the roadsides all around (but mostly north of) Windhoek. Very abundant, very impressive, and very important ecologically.

Its flowers, like so many other species in the genus, vary from uni- to bi-colored (see photo: four lobes sherbet orange and the dorsalmost lobe lemon yellow).

Another photo shows what a typical roadside habitat dominated by this species looks like. (You are not a farmer anywhere around Windhoek without knowing this species. It is THAT abundant.)

Additional photo shows Kyle probing one of the corollas for nectar. We then stick the goo into a refractometer to measure % sugar. Gives a pretty good idea of how lucky or unlucky the pollinators are..

Wild collected, Namibia, Tripp & Dexter #778 & 791 [and on numerous other occasions] (RSA-POM); Photos by Erin Tripp

Petalidium cymbiforme

Petalidium cymbiforme is arguably among the most unique species in the entire genus. It seems clearly related to other species in the “southern clade”, yet still very different. It also has an extremely limited geographic distribution. I’d love to have been around for its (evolutionary) birth… is it really recent? Why isn’t it more widespread? And WHY isn’t someone cultivating this plant? One of just a few species in the genus with stark white flowers. Perhaps the most beautiful of all.

Wild collected, Namibia, Tripp et al. #2078 (RSA-POM); Photo by Erin Tripp

Petalidium crispum

Petalidium crispum commands so much more attention than these photos could ever convey! True to the epithet, its leaves are crisp and borderline NASTY pungent. Kyle and I first encountered this species during our first trip into Marienflüss… sometime around the magic hour… the scorching sun was thinking about sinking. To our tremendous delight, Petalidium crispum absolutely cloaked the lower cliffs of a bright red slope that reminded me, of all places, of the Mojave. The sunbirds didn’t seem to mind our presence and went about their business extracting good stuff from the corollas (see photo).

Much more to a point of *trying* to be serious (it’s hard, when life is so much FUN): there is an extremely interesting evolutionary story going on between Petalidium crispum and is presumed (almost certainly) sister species, Petalidium subcrispum. Ok — forget the ‘presumed’ bit – these two species are nearly identical except for their flowers. Red/bird/crispum and purple/bee/subcrispum. Most remarkable thing: they are nearly sympatric…separated only by the width of the valley (Marienflüss), which is at most a couple of miles wide. They flower concurrently. They have potential to exchange genetic material. So how do they maintain reproductive isolation (or.. do they?). We have a field experiment stewing…

PS 1: Glandular trichomes on calyx of Petalidium crispum become spiny and quite uncomfortable to the flesh when dry.

PS 2: The Himba use this plant as a perfume. Really? Yep – that’s what they told us (via Leevi, who can speak their language well enough). Celebrate diversity – the world is more interesting for it.

PS 3: I love the landscape photo – epitomizes the Kaoko (and Kyle): complete with the latter sitting down in the bottom of the wash looking like a tiny fly, but one with binocs watching birds…

Wild collected, Namibia, Tripp & Dexter #2005 (RSA-POM); Photos by Erin Tripp