July 26, 2019

Case study: unknown

This begins as an unknown. I found it north of the Costco on Orange Grove in Tucson on July 26, 2019 and collected one leaf and a flower.

The flower is yellow. There are 11 ray flowers. The ligules are deeply divided into 3 lobes. Phyllaries in 2 ranks. Pistils have a two part "forked tongue". Ray flowers have no pistil.

Key this out using Arizona Flora

We start on page 830.
Corollas bilabiate? No.
All flowers strap shaped? No.
Are rays present? Yes.
Pappus of bristles? No - it is a large scale.
Pappus missing? No - it is a large scale. -- so H.
(note: an "awn" is a large bristle or spike. Now to page 839 for the key to H.
Receptacle paleaceous? Yes.
Rays white or yellow? Yellow.
Rays fertile, but disks sterile? No, rays are sterile.
Rays persistent and papery?  Unknown, answer no.
Involucre distinctly double? No.
Achenes dorsoventrally compressed? No.
Plants scapose (naked flowering stem)? No.
Pales of receptacle in single series? No.
Leaves parted or pinnate? No.
Rays pistillate or neutral? Neutral.
Achenes thickened or compressed? Compressed.
I am going with Verbesina enceliosa ("crownbeard" or "cowpen daisy").

Description from Jepson Desert Manual: Odor unpleasant. Leaves strigose-canescent Ray flowers fertile (that is bad, but the keys in Arizona Flora indicate otherwise).

Strigose is hairs laying flat on the surface. The top of the leaf is like this, the underside is much more dense, and I would call it canescent.


Have any comments? Questions? Drop me a line!

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