Miller Mtn Brodiaeas
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Brodiaeas On Miller Mountain & The Santa Rosa Plateau
© W.P. Armstrong 19 May 2009

Brodiaea santarosae, B. filifolia & B. terrestris ssp. kernensis

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

Grassland summit of Miller Mountain (Elev. 2953 feet) surrounded by dark green chaparral. The Santa Rosa basalt brodiaea (Brodiaea santarosae) is abundant on basalt in the grassland area. Image taken from Margarita Peak looking north.

Classic Brodiaea santarosae on Miller Mountain. As with BTK, the staminodes are variable. In fact, most of the flowers observed on 20 May 09 did not have discernable staminodes.

Brodiaea santarosae grown from corm collected near the type locality at Clay Hill.

An aberrant Brodiaea santarosae on Miller Mountain. One stamen has a very short filament, while the other two have longer filaments typical of this species.

  Floral Variation in Brodiaea santarosae  

How Large is the Flower of Brodiaea santarosae?

A flower of Brodiaea santarosae compared with a U.S. penny. The perianth of B. santarosae in this image has a spread of 4.2 centimeters, more than twice the diameter of two pennies. The largest B. santarosae on Miller Mountain had a spread of 5 cm, similar to Avenaloca Mesa. As in BTK and other species, size is variable and depends on available moisture and other factors.

  How Large Is The Penny In Above Image  

Size comparison of typical Brodiaea flowers: A = B. santarosae, B = B. orcuttii x filifolia, C = B. orcuttii, D = B. filifolia. All flowers were taken from potted plants and placed on a light box on 5 June 2008. The perianth of B. santarosae in this image has a spread of 4 centimeters.

BTK Variability On Mesa de Colorado

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. Data from Principal Components Analysis (PCA) 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.

Brodiaea species in general exhibit considerable variation in staminode shape and size, which often makes field identification difficult. This is especially true of coastal populations of BTK in southern California, formerly assigned to the taxon B. jolonensis. In fact, local clonal populations may have staminodes quite distinctive from nearby populations. Cross pollination between sympatric species also results in hybrids with intermediate staminodes. Hybrids between parents with different chromosome numbers, such as BTK and B. filifolia or B. orcuttii, are typically sterile and do not produce viable pollen.

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 On Santa Rosa Plateau  
Staminode Variation Of BTK At Camp Pendleton
Staminode Variation Of BTK At Cuyamaca Lake

Where the ranges of two Brodiaea species overlap, hybrids are occasionally found. The hybrids are typically found growing among both parental species. Hybrids may be sterile or fertile depending on the chromosome number of the parents. Anthers of sterile hybrids are filled with clear liquid and cellular debris, but no viable pollen. They may form a small clonal population by asexual reproduction of cormlets. I have never found a hybrid brodiaea that covers hundreds (thousands of acres). In San Marcos I have found two different hybrids: A sterile hybrid between BTK and B. filifolia or B. orcuttii, and a fertile hybrid between B. terrestris and B. orcuttii. Another sterile hybrid between BTK and B. santarosae or B. filifolia occurs on Mesa de Colorado.

  A Sterile BTK Hybrid Brodiaea On The Mesa de Colorado  
A Sterile Hybrid Brodiaea In San Marcos Vernal Pools
A Possible Origin Of The Sterile San Marcos Hybrid
Fertile B. filifolia x B. orcuttii Hybrid In San Marcos
Brodiaea orcuttii in the San Marcos Vernal Pools
Brodiaea filifolia in the San Marcos Vernal Pools

BTK Flower On Miller Mtn With Unusual Growth Form

This unusual BTK flower has multiple perianth segments. The buds are plump and oversized to accommodate 14 segments. A normal flower has 3 outer and 3 inner segments (tepals), a total of 6.

Multiple ovaries (carpels) in above flower with perianth segments folded back.
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.

  Staminode Variation Of BTK On Santa Rosa Plateau  
Staminode Variation Of BTK At Cuyamaca Lake

Brodiaea filifolia in San Mateo Wilderness Area

Brodiaea filifolia in the nearby San Mateo Wilderness Area. It has short filaments (less than 2 mm long) and narrow-filiform, short staminodes.

Additional Images From Miller Mountain

View looking south toward Margarita Peak.

Lichens on Santa Rosa Basalt surrounded by desiccated Selaginella bigelovii.

Crustose lichens on metamorphic rock.

  Rock Formations On The Santa Rosa Plateau  
Rock Lichens On The Santa Rosa Plateau

Foliose lichens on pinkish metamorphic rock.

Grassland summit at west end of Miller Mountain.

View looking north toward Elsinore Peak.

Polemoniaceae: Leptosiphon (Linanthus) liniflorus (Great Basin Linanthus)

Additional Images From Mesa de Colorado

Polemoniaceae: Navarretia prostrata (Prostrate Navarretia)

  Navarretia prostrata On Mesa de Burro  

Poaceae: Orcuttia californica (California Orcutt Grass)

  Orcutt Grass On Mesa de Burro  

Hydrophyllaceae: Phacelia imbricata ssp. patula (Imbricate Phacelia)

  See Caterpillar Phacelia (P. cicutaria var. hispida)  

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