Case study: Baileya multiradiata

There are three Baileya species. B. pauciradiata, B. pleniradiata, and B. muliradiata. My specimen has many more than 8 ray flowers, so that eliminates B. pauciradiata. The next question in the genus key is about ligules (the ray flowers). How long are they? Mine measure about 11mm -- and they are distinctly cleft into 3. This could be B. pleniradiata, but another characteristic mentioned in the description is that B. multiradiata branches at the base of the plant, whereas B. pleniradiata branches along the lower 1/3 of the stem. So B. multiradiata it is. Arizona Flora notes that B. pleniradiata cannot always be distinguished from B. multiradiata.

Cutting up the flower, I see no pappus. The pistil is divided into two. Even the ray flowers have a pistil, but I don't think the ray flower has anthers.

Key this out using the Jepson Desert Manual

Let's go back to the Asteraceae family key in the Jepson Desert Manual.

The first question is whether or not it has ligules (ray flowers).  It does.
Is the head radiate or not?  It is radiate, with both disk and ray flowers.
Does the receptacle have chaff scales or not?  It does not, it is bare.
Does it have a pappus?  It does not -- this takes us to group 10.

Note the question about the receptacle.  I am tempted to think that it would be
a good practice when starting to key out any Asteracea to pluck flowers off of
a good part of the receptacle if not all of it.


Now for the group 10 key.

Are the leaves opposite or alternate?  They are alternate.
Is it a shrub or a herb?  It is a herb (maybe a subshrub).
Are the ray corollas white or yellow? They are yellow.
Is the plant glandular-hairy or tomentose? It is tomentose.


Next it asks a question about old flowers.  It wants to know if the ray corollas
are papery and persist or if they whither and fall off.
I don't know (and this is where keys like this "bottleneck").
The choice that the persist and turn papery would take me to Baileya.
Otherwise I go to Eriophyllum or Monolopia.

 Key this out using Arizona Flora

We start on page 830.

Are some of the corollas distinctly bilabiate? No.
Are all flowers hermaphrodite with strap shaped corollas? No, not all of them.
Are rays present? Yes.
Is there a pappus? No -- this takes us to group G.


We are now on page 837

Are the rays white or yellow? They are yellow.
Is the receptacle chaffy? No.
Are the phyllaries imbricate in several series or in 1 or 2 series.  In one series.
Are the phyllaries separate or united?  Separate.
Are the heads one or two flowered or many flowered?  Many flowered on terminal peduncles.
Are the plants wooly or not?  Wooly.


Now we get to the same question Jepson asked us about the ray flowers being persistent and
becoming papery.  If so, it is Baileya, if not, it is Eriophyllum.


The stems and leaves (and phyllaries) are very wolly, as though the entire plant is covered in white felt.

Comments

Notice how the two keys get us to the same place in entirely different ways.
Here is the genus description from Arizona Flora:


Low floccose-woolly herbs.  Leaves alternate, pinnatifid to entire.
Heads solitary or cymose, long peduncled, radiate, yellow, rays persistent,
becoming paper, reflexed in age.  Achenes striate, epappose.


Here is part of the description from the Jepson Desert Manual:


Canescent-tomentose.  Generally branched only at the base.
Leaves mostly basal and on lower stems.  Pinnately divided.
Heads solitary.  Phyllaries 5-8mm.  Ray flowers 50-60 in
more than one series.




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