Equisetum Funstoni A. A. Eaton, Fern. Bull. 11: 10-12. 1903 (excluding forma polystachyum).
Equisetum laevigatum f. variegatoides A. A. Eaton, Fern Bull. 11: 43- 1903.
? Equisetum hiemale var. herbaceum A. A. Eaton, Fern. Bull. 11: 108-9. I903.
Similar to the specific type but very rough and the bases of
the caducous teeth are more strongly incurved. Eaton described
the spikes of E. Funstoni as "not apiculate as in the rest of the subgenus."
H. laevigata has non-apiculate, i. e., rounded, spikes and
E. Funstoni as distributed by Eaton has some of the spikes apiculate.
The parenchyma is sometimes divided by the vallecular
bast, sometimes not. Equisetum laevigatum f. variegatoides and
Equisetum Funstoni f. caespitosum as distributed by Eaton are to
be differentiated by only one character; the stems of the former
are prostate, ascending, or erect, while those of the latter are
ascending or erect—a distinction without a difference. Both have
prominently white-bordered teeth fading to white throughout.
There seems therefore to be no good reason for keeping Funstoni
separate from laevigata. It has been collected in Wisconsin,
Nebraska, Kansas, Wyoming, Utah, and California.