Translations:Benutzer:Arian/Klett-Mini-Test/1626/en

Field horsetail has no primary roots. Its fine, thread-like roots, directed downward into the depth, are shoot-borne; they arise from the internodes of the rhizome shoots. Toward late autumn, oval swellings form on the near-surface horizontal rhizomes — nutrient reserves for the spring growth, above all for the fertile reddish-brown sporangiophores that shoot up first. Such a one bears the hexagonal sporangia in a spindle-shaped arrangement. After the spores ripen, the fertile shoot dies away rapidly. The dust-fine spores are carried off by the wind and germinate as soon as they reach what is moist and watery. From the germinating spores a root-like tip emerges first; there then develops a greening, algae-like prothallium. "Up to this stage, field horsetail is a green water plant." The prothallia appear in two kinds. One kind of prothallium forms rounded spermatids that can move freely through the water with the help of two flagella. The other kind of prothallium forms egg-cells, which are fertilised by the free-swimming spermatozoa. After fertilisation, the shoot of the field horsetail — growing vertically both upward and downward — leaves the watery phase and joins itself to what is solid in the earth and to the forces of the sun. Both, the fertile and the vegetative shoots alike, develop from the rhizomes that press forward into the deeper zones of the soil and take root there.