Fendler’s Bladderpod

4 Mar

One of the first wildflowers to pop up like little yellow stars in southwest Texas is Fendler’s Bladderpod (Physaria fendleri). Starting last week, these tufts of small yellow flowers are marking many of the desert areas like globs of bright jewels.

Here again was an adventure in identification for several reasons. And I will outline how I pursued identifying this plant. Most of the yellow flowers we see with non-fused petals belong to the very large family Asteraceae, or the sunflowers, and have multiple flower petals (more than 4 petals/flower). However, a few yellow flowers have only four or less non-fused petals. Those usually belong to a different family of plants: the Brassicaceae, or mustard family.

Fendler’s Bladderpod

Once the flowers were narrowed down to the family, then one must use details of leaves, seed, and growth habit to correctly identify the plants. This process is called ‘plant systematics’, most commonly referred to in plant guides as ‘keying’ a plant based on their parts. But that also has limitations, as I will explain in a bit.

When the flowers were keyed in the mustard family and in a genus (Lesquerella), sometimes collectively called ‘bladderpods’, the next step was to determine which species this plant was. This was more difficult because the flowers and leaf shape are typical of two species: Gordon’s Bladderpod (L. gordonii )and Fendler’s Bladderpod (L. fendleri). They both have tiny silver hairs on their leaves and stems. And they grow in the same region!

The only differences between these two species are that the Gordon’s Bladderpod is an annual, whereas the Fendler’s Bladderpod is a perennial. Because of that, the Gordon usually begins flowering a month or two later than the Fendler’s. Additionally, the Gordon’s usually have longer stems that may lie on the ground and turn up at the tips, and thus they have a more open appearance. The Fendler’s, on the other hand, often grows in more compact and upright clusters.

The other issue with identification of these plants is in the names. Again, I ran into reclassification of an entire genus of plants where the literature, especially plant guides, is very slow to catch up. Including many online plant databases (even state and federal).

The first specimen of this plant was collected in 1847 from near Santa Fe, NM, by Prussian-born natural historian Augustus Fendler. From the specimen, the plant was named and characterized by the famous botanist Asa Gray as Vesicaria fendleri.  Years later (1888) the curator of the Gray Herbarium (of Harvard University), Sereno Watson, who was appointed by Gray, renamed the plant Lesquerella fendleri.

Now, move ahead in time to 2002 when a team of botanists and biologists petitioned the organizations involved in taxonomical name conventions to move all the plants of the genus Lesquerella to another existing genus, Physaria. Why would they propose that change? Traditionally plants have been categorized and named based on comparative data: morphological, ecological and distribution. However, in the past two decades the addition of more sensitive and technical tools, such as molecular biology and genetics, have been applied to confirm similarities and separate differences. Consequently, some organisms are now determined too similar rather than more different and are reclassified together in the same genus, even species. Conversely, some molecular differences are important enough to separate some species that were once classified together.

When in doubt, I have always turned to a database used by nearly all biology, molecular and genetic scientists, and which is continually updated, sometimes more than daily. It is crucial for all scientists to keep up with changes in scientific data and reporting, which truly reflects the dynamic world of life sciences and discovery. Although many of the media and even federal plant databases still use the old naming convention, the genus Lesquerella  is no longer accepted or correct.  As of now most of the species within that genus are now included in the official genus name, Physaria. Unfortunately, it may take another five or more years for that name to propagate through all the databases and into the literature, including the nature guides everyone uses for identifying plants.

An ending note about these two bladderpods: they can be poisonous to livestock, especially horses. The seeds especially contain a large amount of oil that can be toxic if eaten in excess. On the other hand, the Fendler’s Bladderpod is now being considered as a commercial source of oil to make plastics, grease and as an ingredient in cosmetics, mostly to replace castor oil. Me, I just like enjoying their little yellow mounds of stars on the desert floor.

Fendler’s Bladderpod


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