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The Santa Rosa Basalt Brodiaea | 
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Key To The Species Of Brodiaea In Southern California
This is a key to all five species of Brodiaea in mainland southern California, including one hybrid between two of those species, and notes on how to detect other hybrids.
B. jolonensis is not included in this key, since all southern California specimens previously determined as that species have numerous differences from specimens of B. jolonensis from the type locality of Jolon, CA, and are nearly identical to specimens of B. terrestris ssp. kernensis. No southern California specimen that we have examined has the distinctive purple ovaries of B. jolonensis. (Several other species of Brodiaea have ovaries with a trace or tinge of purple that is very different from the uniformly-purple ovaries of B. jolonensis.) See Brodiaea jolonensis Doesn't Exist In Southern California for more information.
In this key, the properties of the staminode refer only to its free portion and do not include the lower continuation of the staminode that is fused to the outer perianth.
A pictorial key is presented first to the five species, with a word key below to the five species plus one hybrid between two of the species. See also Wayne Armstrong's Images of Brodiaea Species in Mainland & Insular California.
Pictorial Key
The five species are separated by the presence (or absence) and shape of the staminodes of the flower, as well as sometimes by filament length.
A staminode is a structure similar to a stamen, but that lacks anthers. The staminodes are indicated in several of the following pictures.
The filament is the stalk under the yellow anthers that hold the pollen sacs.
| Staminodes oblong to rectangular in outline, tapered only near tip if at all: | Staminodes generally erect, edges flat to inrolled, sometimes hooded, generally purple, the most common species in southern California B. terrestris ssp. kernensis | Staminodes recurved, edges flat, not hooded, pointed at tip, generally white, present only at Mission Trails Regional Park B. elegans ssp. elegans |
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| Staminodes filiform or uniformly tapered from base to tip: | Filaments 0-1.5 mm; staminodes 1.0-4.5 mm long, reflexed against perianth, uniform within each flower B. filifolia | Filaments 2-8 mm; staminodes 0.0-7.0 mm long (absent in 10% of flowers), recurved to erect, often variable in length within a flower; present only at the Santa Rosa Plateau B. santarosae |
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| Staminodes 0 in all flowers; present only in San Diego County and in Riverside County just immediately north of San Diego County at Rainbow: | B. orcuttii
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The species also separate into two groups of flower size. B. elegans, B. santarosae, and B. terrestris ssp. kernensis have flowers typically 30-45% larger than the flowers of B. filifolia and B. orcuttii. The photograph below shows our first sampling of populations of B. filifolia and B. santarosae, before we had any idea what species our samples of B. santarosae actually were. The two large flowers are B. santarosae; the two small flowers are B. filifolia. (The sampling was geographically-based; these four flowers are representative of the collected flowers.)
The difference is especially remarkable since the samples of B. filifolia were collected in a moist area surrounding the largest vernal pool on the Mesa de Colorado at the Santa Rosa Plateau, and the samples of B. santarosae were collected on top of Clay Hill just west of the Mesa de Burro, which was very dry on 1 June 2006.
The median flower lengths of B. filifolia and B. orcuttii are 20.2 and 21.9 mm, respectively, compared to lengths of 28.3 and 29.4 mm for B. santarosae, and B. terrestris ssp. kernensis.
Of course, sizes are impossible to deduce from a photograph without a scale in the picture.
Word Key
1 Staminodes 0 in all flowers................................................. B. orcuttii
1' Staminodes present in 90-100% of flowers .......................................(2)
2 Staminodes oblong to rectangular in outline, tapered only near tip if at all... (3)
2' Staminodes filiform or uniformly tapered from base to tip ..................... (4)
3 Staminodes generally erect, edges flat to inrolled,
sometimes hooded, generally purple............................B. terrestris ssp. kernensis
3' Staminodes recurved, edges flat, not hooded,
pointed at tip, generally white; Mission Trails Regional Park......B. elegans ssp. elegans
4 Filaments 0-1.5 mm; staminodes 1.0-4.5 mm long, reflexed against perianth.....B. filifolia
4' Filaments 2-8 mm; staminodes 0.0-7.0 mm long, recurved to erect.....(5)
5 Perianth length 19-24 mm; style 8.0-9.5 mm; ovary 4.0-5.0 mm;
anther 5.0-5.5 mm; San Marcos...................................B. filifolia X B. orcuttii
5' Perianth length 24-36 mm; style 10.5-17.0 mm; ovary 3.5-8.2 mm;
anther 5.4-8.9 mm; Elsinore Peak to Miller Mountain..........................B. santarosae
Because only three specimens of B. filifolia X B. orcuttii are known, the range of measurements for it in the above key will require slight extensions as more specimens are found. However, principal component analysis indicates that those extensions will be much smaller than the differences from B. santarosae.
Hybrids of B. terrestris ssp. kernensis with any of the species of B. filifolia, B. orcuttii, or B. santarosae are readily recognized by the absence of pollen in the stamens. The other parent is most easily determined by the geographic location of the hybrid, since these species are not found together except at San Marcos, where both B. filifolia and B. orcuttii are present. At San Marcos, it requires detailed measurements to determine which of those two species is the other parent.