Monographs Details: Hippochaete laevigata var. eatonii Farw.
Authority: Farwell, Oliver A. 1916. The genus Hippochaete in North America, north of Mexico. Mem. New York Bot. Gard. 6: 461-472.
Description:Distribution and Ecology - Wiards Siding, Mich., Farwell 2159 1/2, 2159 1/3, June 25, 1910. Rochester, Mich., Farwell 2706 1/2, 2710 1/2, June 11, 1912; 3643 1/2, May 26, 1914; 3694 1/2, June 8,1914. Algonac, Mich., Farwell 3640a, July 26, 1914.
Equisetum hiemale var. intermedium A. A. Eaton, Fern. Bull. 10: 120. 1902, as to the annual plant.
Externally, this variety can be distinguished from the typical species only by the roughness of the stem and the occasionally apiculate spikes. The anatomy is very variable, sometimes that of the species, sometimes that of H. prealta var. affinis; now intermediate when the parenchyma is continuous, and now combining both types when both the carinal and vallecular basts divide the green parenchyma, splitting it into irregularly triangular blocks. It may be found alone, associated with H. laevigata, H. prealta, or its var. affinis, or with all of these. In the original description of Equisetum hiemale var. intermedium, Eaton included annual and evergreen plants with teeth that were caducous, deciduous, and persistent. In the seventh edition of Gray's Manual he had restricted the variety to the evergreen plant with caducous teeth. This left the evergreen plant with broader sheaths and persistent teeth and the annual plant with caducous teeth without names. For the former I have adopted Engelmann's varietal name of scabrella; to the latter I give the varietal name Eatonii. The first stems of the season fruit in June and perish in July and August when the later stems are fruiting and others just coming up. At this time it simulates H. prealta var. intermedia but is quickly and readily differentiated by its annual stems, which have not the bright green of that variety. Some plants have completely perished before winter sets in while others in greater or less degree survive the winter but these parts have perished before the new growth of the season begins in May. Where this variety grows in profusion it is not an uncommon thing to see in March, just after the snow has disappeared, its long stems chalk-white and intact lying flat upon the ground, crossed in all directions. When disturbed, however, they will fall apart and crumble into powder. The stems like those of the species may be single or caespitose, simple or branched, and often four feet in height. I have not seen any with spike-bearing branches.
Distribution:United States of America North America