Notes on Ageratina in Texas

Shrubby Boneset (Ageratina havanensis)
White Snakeroot (Ageratina altissima)
Other species (A. wrightii) less than 5 RG observations
BONAP range
Glossary of Leaves for convenience

A. havanensis A. altissima
Form Shrub Herbaceous Perennial
Woody Stem?

Yes
(though younger plants may not develop this yet)

No
Leaf shape

Deltate to broadly ovate or somewhat hastate
(Leaning towards triangular?)

Deltate-ovate to ovate or broadly lanceolate
(Can get more ovular in shape)

Petiole length 3-10 mm 10-30 mm
Leaf margins

Dentate, sometimes bluntly
and bordering on crenate

Coarsely and doubly serrated/incised

Cypsellae texture
(the seed)

 Hispid (Stiff hairs/bristles) Glabrous

It's been observed that the anther filaments do not stick out as much/are less prominent. This does seem true... Not confident about reliability yet but looks promising.
Also according to FNA,
"Ageratina havanensis apparently is the only species of the genus in the flora area with evergreen-persistent leaves."

Links:
FNA:
http://beta.floranorthamerica.org/Ageratina_havanensis
http://beta.floranorthamerica.org/Ageratina_altissima
GBIF (Herbarium specimens)
https://www.gbif.org/species/5400768 A. havanensis
https://www.gbif.org/species/5400552 A. altissima

https://www.inaturalist.org/observations/64215732

Posted on December 03, 2021 06:12 PM by arnanthescout arnanthescout

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