These enenlies are as a rule so conspicuous that we do not look on their depredations as diseases, though the gradual deterioration of hay under the exhausting effects of root-parasites like Rhinanthus, and the onslaught of Cuscuta when unduly abundant, should teach us how unimportant to the definition the question of size may be.
Cuscuta has a thread-like, spirally twisted embryo with no trace of cotyledons.
Cuscuta contains nearly too species in the warmer and temperate regions; two are native in Britain.
Convolvulus arvensis (bindweed) is a pest in fields and gardens on account of its wide-spreading underground stem, and many of the dodders (Cuscuta) cause damage to crops.
- Cuscuta europaea, Dodder.
- Cuscuta glomerata.
In Cuscuta (Dodder) (q.v.), however, we have an exception.
Such aberrant forms are to be regarded in the same light as Cuscuta and Orobanchaceae, for example, among Phanerogams. As these non-green plants do not cease to be classed with other Phanerogams, so must the forms in question be retained among algae.