|Scientific name:||Equisetum sylvaticum L.|
|English name:||wood horsetail|
|Plant Family:||Equisetaceae, Horsetail family, Fräkenväxter|
|Life form:||Perennial, deciduous, homosporous pteridophyte|
|Stems:||Sterile stems are green with lacy branches and grow up to 28 inches (70 cm) tall. Fertile stems are at first unbranched and lack chlorophyll but become branched and green after spores are released.|
|Leaves:||Scales fused into sheaths around stems and branches; sheaths of sterile stems 3 - 12 mm long, green below, brown upwards, with 3 - 5 brown teeth, joined into several broad lobes; sheaths of fertile stems similar to but much larger and looser than those of common or meadow horsetail.|
|Flowers:||No flowers; instead, strobili, cones, usually 3 cm long and are borne on short stalks at the apices of fertile stems; Gametophytes (produces male or female gametes (or both), by a process of cell division called mitosis) only establish on recently exposed bare mud, such as around resevoirs or streambanks following flooding. Wood horsetail has a very limited spore dispersal period, and spores are short-lived. Male gametophytes grow at a much slower rate than females. There is also evidence of early male mortality. Gametophytes reach sexual maturity at 3 to 5 weeks and then produce a constant supply of gametes until death. The sex ratio of a population is determined by environmental conditions; female gametophytes are more likely to be produced under favorable conditions. The frequent occurence of Equisetum hybrids suggests, however, that sexual reproduction is a common occurrence in this genus.|
|Flowering Period:||May, June|
|Fruits:||Produces spores instead of fruit|
|Habitat:||Throughout the country, all types of forests, but also on heaths above the tree line; very moist to wet, nitrogen-poor soils|
Derivation of the botanical name:
Equisetum from the Latin equis, "horse" and seta, "bristle".
Equisetum is a primitive plant, a descendat of huge trees that lived in the Paleozoic era (542–251 million years ago).
It produces two different stalks. One is the fertile "joint-grass", the other is the sterile "horse-tail". The fertile stalk produces a cone-like structure at the top, which is covered with spore-producing scales.
sylvaticum, from the Latin Sylva, "forest", and aimed at the plant site.
Distinguished from our other Horsetails by the elegant whorls of slender, recurved branches, generally twelve or more branches to a whorl, which are very about 5 inches long, quadrangular and beset by several secondary whorls so that the plant resembles a miniature pine tree.