Tuesday, June 11, 2013

What is the Eriogonum Subg. Oligogonum on Bonanza King, Trinity Mountains, Trinity County, CA?

The prostrate, small mat buckwheat that grows on the summit of Bonanza King Trinity County does not key clearly to any known taxon.  These plants are Subg. Oligogonum exactly: low spreading plants with stipe-like perianth bases.  The plants we collected are female-sterile: at both sites where specimens were obtained, the flowers have only stamens.  This would indicate that possibly this species is gamodioecious, and perhaps we did not seek out plants with perfect flowers.  The olive-green, glabrate upper leaf surface of the Bonanza King plants are is similar to E. marifolium: that species has very obvious morphologically different males and females which could easily pass for different species.  The Bonanza King plants have an extremely congested inflorescence: the involucres are subtended by very  rudimentary (ca. 1 mm long) inflorescence branches, resulting in the inflorescence appearing as a single head.   The Bonanza King plants have a whorl of bracts that immediately subtend the inflorescence, and they lack a mid-scape bract whorl.  Immediate subtention in this instance suggests a evolutionary pathway where a secondary involucre becomes adaptive, with inflorescence branches mal-adaptive.

The Bonanza King plants might pass as a race of the highly polymorphic Eriogonum umbellatum (at 41 treated variants, the most racially complex North American endemic taxon, just beyond Astragalus lentigenosus with ±34 infrataxa, and Lepidium montanum with ±22  infrataxa).   What a field excursion it would be to chase down these “dirty 97”: an Amazing Race requiring a hand lens and 25,000 miles of travel.

The Klamath Mountain region is home to several rare, endemic taxa of Subg. Oligogonum: E. diclinum, E. ursinum, E. libertinii, E. congdonii, E. ternatum, E. hirtellum, E. kelloggii, E. alpinum  Adding E. nervulosum of the high North Coast Ranges, this region is a definite knot of Oligogonum-isms. The buckwheats on Bonanza King might be yet another novel taxon in this complex.

Plants are wierd: any field trip that you return home from with a plant you can not put a definite name on is worth gas at $10 a gallon!

The single specimen of a buckwheat from Bonanza King, CHSC105754, labeled as E. alpinum is very probably E. lobbii, which has characteristic inflorescences which orient directly at the ground surface, and which we saw, not-yet in flower on, Bonanza King in a snowbed site in the lee of the peak.

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