Tag Archives: Boechera

The Center of Diversity for Boechera

Did you know that Mono County is home to more species of Boechera (“rock-cress,” in the mustard family) than any other county in the United States?

Boechera retrofracta

Boechera puberula north of Masonic.

Neither did I, until I ran across a web page with 103 maps showing the number of species per county for the “Largest Genera in Continental North America”. This analysis is part of the Biota of North America Program (BONAP) (Kartesz 2015a, 2015b). The overall distribution patterns these maps reveal are interesting, and perusing the maps for familiar genera and favorite places is also enlightening. For example:

Inyo County, CA boasts the greatest diversity of Eriogonum (55 spp.), Phacelia (43 spp.), Lupinus (40 species), Cryptantha (24 spp.), and Ericameria (24 spp.).
San Bernardino County, CA has the greatest variety of Mentselia (24 spp.), Gilia (23 spp.), and Galium (20 spp.).
Garfield County, UT has the greatest numbers of Astragalus (59 spp.), Penstemon (31 spp.), Oreocarya (16 spp.), and Cymopterus (11 spp.).
Juncus is most diverse in Plumas County, CA (33 spp.).
Castilleja is most diverse in Fresno County, CA (21 spp.).
Artemisia is most diverse in Fremont County, WY (18 spp.) and nearly as diverse in Elko  County, NV.
Calochortus is most diverse in Kern County, CA (17 spp.).
And so on. As one might expect, the larger and more physiographically diverse counties are favored to have high numbers of species for large genera in the arid western states (e.g., Inyo, San Bernardino, Nye, and Coconino Counties). Perhaps grouping some adjacent small counties together would shift the locations of some hot spots.

Boechera retrofracta

Boechera puberula up close.

Mono County, then, is the center of diversity for Boechera, with 36 species (listed below). Sixteen of these are known or appear likely to occur in the Bodie Hills. No wonder I didn’t find them all during my field work 30-some years ago, and no wonder I gave up trying to key all my specimens and shipped them off to Reed C. Rollins (1911–1998), a professor of botany at Harvard University, and the renowned expert on many Cruciferae, including what we then called Arabis. He kindly annotated them all and shortly thereafter cited several of my specimens in describing Arabis bodiensis (now Boechera bodiensis) as a new species from material previously identified as Arabis fernaldiana var. stylosa. Rollins (1982) wrote, “Furthermore, an extensive sampling of Arabis populations of the Bodie Hills by Tim Messick has shown that what we name A. bodiensis below is consistent in its characters and is present on many appropriate sites throughout the area. This adds up to the necessity of recognizing the Bodie Hills material as an undescribed species.”

Boechera sp.

Boechera sp.at Grover Hot Springs in Alpine County.

The rock cress species are fairly challenging to identify. One often needs flowers (for their color), leaves (for their shapes and trichomes or hairs), intact fruits, and mature seeds to run a specimen successfully through the keys. Most Boechera plants don’t provide all of these parts in good condition all at the same time. One may need to key the same population in both spring and summer (taking notes and photographs) to do the job well. Familiarity and practice make for easier and more reliable identifications in any large group of plants, so the key to getting good with Boechera may be to live in or near Mono County.  Or Inyo County, which has nearly as many Boechera species.

Boechera sp.

Boechera sp. at Travertine Hot Springs

And finally, the elephant in the room is of course: How does one pronounce the name Boechera?  “BOH-chera” (long O) appears likely or even obvious to most Americans, but “oe” in Latin names is always pronounced “ee” (long E), as it should be in Oenothera or Oenanthe. So is it BEE-chera? Boechera is named for Tyge W. Boecher (1909–1983), a Danish botanist, evolutionary biologist, plant ecologist, and phytogeographer. But the Danish spelling is Böcher (with an o-umlaut), and this would suggest the “oe” (or ö) should be pronounced more like the “oe” in the French words oeil (eye) and oeuvre (an artist’s collected works). This sound can’t be spelled in English, but “BUH-chera,” with a listless enunciation of the first syllable, comes close. Or maybe “BOO-chera.” Take your pick.

Boechera sp.

Boechera sp. in Bridgeport Canyon. These are not especially showy plants.

The 36 species of Boechera in Mono County (according to CalFlora) are listed below. Those known or likely to be in the Bodie Hills are followed by a “(BH)”.

  1. Boechera arcuata (BH)
  2. Boechera bodiensis (BH)
  3. Boechera cobrensis (BH)
  4. Boechera covillei
  5. Boechera davidsonii
  6. Boechera depauperata
  7. Boechera dispar
  8. Boechera divaricarpa
  9. Boechera elkoensis (BH)
  10. Boechera evadens (BH)
  11. Boechera glaucovalvula
  12. Boechera howellii
  13. Boechera inyoensis
  14. Boechera lemmonii (BH)
  15. Boechera lyallii (BH)
  16. Boechera microphylla
  17. Boechera pauciflora (BH)
  18. Boechera paupercula (BH)
  19. Boechera pendulina
  20. Boechera pendulocarpa (BH)
  21. Boechera perennans
  22. Boechera pinetorum
  23. Boechera pinzliae
  24. Boechera platysperma (BH)
  25. Boechera puberula (BH)
  26. Boechera pulchra (BH)
  27. Boechera rectissima
  28. Boechera repanda
  29. Boechera retrofracta (BH)
  30. Boechera shockleyi
  31. Boechera sparsiflora (BH)
  32. Boechera stricta (BH)
  33. Boechera suffrutescens
  34. Boechera tiehmii
  35. Boechera tularensis
  36. Boechera xylopoda

References:

Kartesz, J.T., The Biota of North America Program (BONAP). 2015a. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C.

Kartesz, J.T. 2015b. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP) [maps]

Rollins, Reed C. 1982. Studies on Arabis (Cruciferae) of Western North America II. Contributions from the Gray Herbarium. 212: 103-114

Boechera sp. with Puccinia rust

Boechera becomes infected with the yellow, flower-mimicing Puccinia rust. (See the Puccinia post.)


Copyright © Tim Messick 2016. All rights reserved.
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Floral Mimicry in the Bodie Hills

Soon it will be early spring in sagebrush country, and insects will be eager to find plants that provide nectar, pollen, or other yummy flower parts for food. Many early-spring flowers are in the mustard family (Brassicaceae) and buttercup family (Ranunculaceae). Many mustards and buttercups have bright yellow flowers. Bright yellow is a good color for attracting insects, because this color is also bright in ultraviolet, which many insects see well.

Puccinia monoica

But not all bright yellow plants are flowers. The yellow stuff above and below is a parasitic fungus—a type of rust (order Pucciniales)—growing on the leaves of a rock cress (Boechera sp.). The rock cress hasn’t flowered yet, and because of the fungal infection, this plant won’t produce real flowers at all this year. It will attract insects, though, because the fungus has produced zillions of little bright yellow spermatogonia on the leaves that cause the leaves to look superficially like flower petals. These spermatogonia exude spores (spermatia) that are carried by the visiting, feeding insects to other rock cress plants, just as they would normally carry pollen from flower to flower.

This particular rust is Puccinia monoica (no relation to Mono County, as far as I can determine, though I’m not sure what the name refers to). Puccinia was named after Tommaso Puccini (1749-1811), a professor of anatomy in Florence, Italy.

Floral mimicry is a deceitful, counterfeit way to make a living, but the rusts are obligate parasites and they have few options. Not all rusts are floral mimics, but those practicing this ruse are experts in their trade and are highly successful because if it. The rusts, like many parasites, have beautifully complex life cycles. Puccinia monoica infects additional hosts (the grasses, Koeleria, Trisetum, and Stipa, all of which live in this area), for another stage in its reproductive cycle. While on the grasses it does not engage in floral mimicry — that would be wasted effort indeed.

Puccinia monoica
Puccinia should not, however,  be confused with Puccinellia, which is not a fungus, but a grass, Alkali grass. Three species (P. distans, P. lemmonii, and P. nuttalliana) occur in the Bodie Hills — at Travertine Hot Springs and other moist alkaline places in the region and across much of western North America. Puccinellia was named after another Italian, botanist Benedetto Luigi Puccinelli (1808- 1850).

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Phragmidium is another genus of rusts that infects leaves, stems, fruits, and flowers of roses, blackberries, and other members of the rose family (Rosaceae). Here’s one on Woods rose (Rosa woodsii) near the stream in the aspen grove in Masonic Gulch, near Lower Town Masonic.

Phragmidium

Phragmidium rusts are not floral mimics, and their spores may be largely wind-dispersed, but the bright orange of their spore-filled uredinia may attract some insect attention.

Phragmidium

 

 


Copyright © Tim Messick 2016. All rights reserved.
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