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Staminode Variation in Brodiaea terrestris ssp. kernensis
On The Santa Rosa Plateau of Riverside County, Calif.

Note: The Brodiaea, that I referred to as "Coastal BTK," is listed as a possible
undescribed taxon under B. jolonensis in the revised Jepson Manual II (2011)

Until a satisfactory name is applied to these populations, I will refer to southern California populations previously called "Brodiaea jolonensis" as "Coastal BTK" and mountain populations previously called "Brodiaea terrestris ssp. kernensis" as "Montane BTK."

Brodiaea terrestris ssp. kernensis (BTK), including coastal & montane forms, is a large and diverse complex that extends from Santa Barbara and Kern Counties to the Mexican border. PCA data thus far indicates that BTK is one variable species that does not warrant segregation. BTK intergrades into variable populations on the Santa Rosa Plateau of Riverside County and at Cuyamaca Lake and Camp Pendleton in San Diego County. Fertile clonal variants have hooded staminodes, staminodes that are flattened and strap-shaped or inrolled along upper margins, and narrow staminodes that are tapered toward the apex. In addition, the staminodes may be erect, leaning slightly outward or leaning inward. Whether the anther connectives of BTK have a dentate appendage or V-shaped notch is also quite variable, particularly in Kern County populations. This trait is of little value in separating populations of BTK, but is fairly consistent in populations of B. terrestris ssp. terrestris (BTT) in San Luis Obispo and Monterey Counties. In general, populations of BTK in southern California lack a well-defined dentate connective; however, this trait occurs in some Kern County populations. These traits are apparently not under selection pressure and hence exhibit a lot of variability. In addition to clonal variants, there are occasional sterile hybrids between BTK and other sympatric populations, such as B. filifolia and B. orcuttii.

The flower color for Brodiaea species on this page is blue-purple to violet. In the following images
I have attempted to match their true color;  however, they may appear different on your monitor.

The following images show the remarkable variation in staminodes of Brodiaea terrestris ssp. kernensis on the Santa Rosa Plateau of Riverside County, California. They are within the Santa Rosa Ecological Reserve of the Nature Conservancy. The population includes staminodes that are erect and curved outward. They range from strap-shaped and toothed to hooded and slightly inrolled along margins. Some are inrolled along their entire length. The hooded staminodes are similar to populations of Coastal BTK in San Diego County. The erect, inrolled staminodes are similar to populations of Montane BTK in San Diego County. It seems that the Coastal BTK and Montane BTK merge into one variable population on the Santa Rosa Plateau.

Variation in staminodes of BTK on the Santa Rosa Plateau of Riverside County. They range from strap-shaped and toothed to inrolled and slightly hooded.

1. Strap-shaped and Toothed Staminodes

Note: The above image is a hybrid between BTK and B. santarosae or B. filifolia that grows intermixed in certain areas of the Santa Rosa Plateau. The flat (strap-shaped) staminodes have a slender (subulate) apex (white arrow). Anther sacs of this putative hybrid are devoid of pollen.

  Sterile BTK Hybrid Brodiaea On The Mesa de Colorado  

Probably a variant of BTK. I do not have data on whether the anther is sterile or fertile.

2. Inrolled & Slightly Hooded Staminodes

Note: According to Tom Chester, the above flower type was the most common type observed in May 2006. He did not see the variation shown in the images on this page (taken in May 2005). His observations suggest that staminode shape might be related to rainfall or other variable environmental factors.

3. Inrolled & Outwardly Curved Staminodes

4. Hooded Staminodes Leaning Inward Toward Stamens

5. Staminodes Similar to Montane BTK of San Diego County

 Brodiaea terrestris ssp. kernensis from Kern County. The staminodes are slightly inrolled along upper margins but not hooded. In general, they superficially resemble populations of BTK on the Santa Rosa Plateau and in the mountains of San Diego County. BTK populations in coastal San Diego County often have staminodes that are hooded at the apex; however, hooded staminodes also occur on the Santa Rosa Plateau and Cuyamaca Lake. Staminodes of BTK are exceedingly variable.

6. Narrow (Strap-Shaped) and Pointed

BTK with slender, pointed staminodes. The staminodes are flat and strap-shaped, not inrolled along margin or hooded at the apex like other BTK on the Santa Rosa Plateau. These occur near a small vernal pool on Mesa de Colorado and probably represent a clonal population. The above flowers had abundant pollen. Clonal populations of fertile BTK with slender staminodes like the above images have also been observed in San Marcos and Camp Pendleton.

  Staminode Variation Of BTK At Camp Pendleton  
Staminode Variation Of BTK At Cuyamaca Lake

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