In article , Lar
writes:

I came up with HorseWeed is Marestail, Conyza canadensis
and HorseTail (Field) is Equisetum arvense.


That's correct Lar
Horseweed, Conyza canadensis, is sometimes called Marestail.
It's in the Asteraceae (Family) Flowering plant.
Equisetum, Horsetail, is also sometimes called Marestail when it is in the
form of a green, bushy, jointed sterile stem with whorls of thin branches
It is in the Equisetaceae (Family) and is closely related to ferns.
Equisetum reproduces from rhizomes and from spores.

Also sometimes called Marestail is Hippuris vulgare, Family Hippuricaceae,
an aquatic perennial plant, the upper stem having whorls of leaves, a
flowering plant.

Again the problem of common names rears its head...........

Emilie
NorCal