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Category Archives: Tassel Flowers

Tassel Flowers, Twin Species with Twin Hairs

Emilia fosbergii (usually red, with variations) and Emilia sonchifolia (lilac)

(Emilia is a personal name, but the identity of Emilie or Emile is lost history.  Raymond Fosberg was an American botanist.  Sonchifolia means “leaves like Sonchus,” a related genus.)

Asteraceae

 

Twins!  One with red flowers, the other with lilac.   Every person within the ranges of these two beauty weeds has noticed their bright flowerheads somewhere.    Venus’s paintbrushes.  Native to the Old world,  they grow from the boondocks to Wal-Mart parking lots, often together.    Can’t miss em’.

Emilia fosbergii 3 (1)

Emilia fosbergii, flowers usually red.  By John Bradford.

Emilia fosbergii 4

Emilia sonchifolia, typically lilac.  By John Bradford.

Being so similar, ultra-closely related, and often mixed, I wondered if the two might form hybrids, especially because flower-color intermediates exist.   The tweeners look like obvious hybrids.   But watch out, “obvious” conclusions send innocent convicts to the chair.

There is hybridization afoot, but not what we were thinking.  It happened long ago:   Emilia fosbergii is  the result of an ancient cross between Emilia sonchifolia and another species.    Botanists who study these plants suspect the “other” species to be the red-flowered Emilia coccinea which occurs in the U.S. only as a garden flower.    So did you catch that, E. sonchifolia is a “parent” of E. fosbergii.

The hybrid origins of Emilia fosbergii help explain the color intermediates in a new refreshing light.   One parent species, E. coccinea has bright red to orange flowers, the other parent, E. sonchifolia has lilac blossoms.  Our hybrid species E. fosbergii usually (in Florida at least) tends to be red, and varies to pink or light violet.  In short, it can resemble variably either or its parent species.   It has a full set of chromosomes from each, thus the genetic blueprints for each.

Emilia fosbergii paired hairs

Twin hairs on the “seed.”

The Emilia fruits resemble dandelion “seeds” suspended from a parachute.   The tiny seedy paratrooper (technically an achene) has an unusual feature, twin hairs, side-by-side hotdog-shaped outgrowths.    Recent studies reveal paired functions for the paired hairs.  The first function is to serve as intake ports for water entry as the seed contacts wet soil.   Little “roots.”  The second function is a bit root-ish too:

To release mucilage…remember mucilage glue?…to fix the seed to the soil particles.  It still has a parachute attached and may otherwise blow around, disrupting germination and establishment.


Emilia fosbergii 6

E. fosbergii, so pretty. By John Bradford.

*To rephrase more precisely for those who care:  Emilia fosbergii appears to be an allotetraploid potentially of African origin with one subgenome from diploid E. sonchifolia (well substantiated) and the other subgenome (speculatively) from a diploid biotype of E. coccinea which has diploid and tetraploid biotypes.

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Posted by on July 20, 2017 in Tassel Flowers, Uncategorized

 
 
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