Equisetaceae . . . . Horsetails
Equisetum . . . . . Horsetails
A number of other spp. and hybrids (mostly rare) are recognised
Equisetum arvense . . . Field Horsetail
Abundant - often as a pervasive weed; branches (3)-4 angled with green spreading teeth; stems smooth with small hollow plus row of little hollows, fruiting stems brown appearing before leafy stems
Equisetum fluviatile . . . Water Horsetail
Stems with large hollow >half diameter
Equisetum hyemale . . . Rough Horsetail
Hollow c.2/3 of stem diameter, sheaths with black band at top edge with teeth disappearing with age; uncommon, mostly in N
Equisetum palustre . . . Marsh Horsetail
Lowest branch internode shorter than main stem sheath; stems with hollow <1/4 diameter; Common on wet or marshy ground
Equisetum pratense . . . Shady Horsetail
Branches 3-angled; delicate often drooping to one side, rarely fertile; local in N Br; 6-20 separate teeth at nodes
Equisetum sylvaticum. . . Wood Horsetail
Branched branches, 4-angled (cf shady horsetail) generally drooping at tip; teeth united into 3-6 broad lobes (fig.3)
Equisetum telmateia . . . Giant Horsetail
Damp shady places, though rare in C, E & N Sc
Equisetum variegatum . . . Variegated Horsetail
Small plant less than c.10-15 cm tall; branches 5-angled; local and scattered in Ire and N & W Br; dune slacks to wet stony mountains
Equisetum x litorale . . . Shore Horsetail (E. arvense x E. fluviatile)
Hollow >half diameter; Branches (3)-4 angled with spreading teeth and lowest internode >stem sheath; stems smooth with sheath teeth black w. faint pale edges, bare of branches nr tip; Scattered in wet places around UK (even without parents)
There are a number of other hybrids frequently found.
