Dodder
2 of the 6 encyclopedias on this shelf carry an entry for Dodder. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a peculiar relative of the morning glory . There are some fifty kinds, all leafless, worthless plants that look like pale, unhealthy runners of a strawberry. The flowers are in fleshy green clusters. The characteristic of the dodder is parasitism. The dodder drops its seed in the ground, where it takes root and sends up a tendril-like shoot that fastens itself by suckers to the stem of some other plant. It sends in rootlets to suck the sap and lives on its host, dying away at the ground entirely. There are many common dodders-all agricultural pests-as clover dodder, flax dodder, hop dodder, etc. Often dodder is a tangled mass of green and yellow threads. A search in a tangled patch of weeds, sunflowers, and the like is likely to reveal the presence of dodder. The vines have no leaves and need none. The work done by leaves is done for them by the leaves of the host plant. See Parasite ; Fungus
Collier's New Encyclopedia (1921)
the common name for plants of the genus Cuscuta. There are several species; they are slender, thread-like, twining, leafless parasites, involving and destroying the whole plants on which they grow. Two species are natives of England: C. epithymum, which grows abundantly on ericas, and C. europæa, upon thistles and nettles or other soft plants within its reach, bringing them final destruction. Within a few decades two other species have accidentally been introduced: viz., flax dodder and clover dodder. The first destroys whole fields of flax, and the latter preys to a great extent on clover, both plants being the cause of great losses to the agriculturist. In India, some species are very large and powerful, involving trees of considerable size in their grasp.
What Has Changed in the Last Century
Aiton's guess in 1910 that dodder is "a peculiar relative of the morning glory" has been vindicated: after decades in which Cuscuta was often given a family of its own, Cuscutaceae, DNA work has placed it firmly back inside the morning-glory family, Convolvulaceae. The count has grown too, from Aiton's "some fifty kinds" and Collier's "several species" in 1921 to roughly 200 recognised species. What neither account could imagine is how the seedling finds its victim: experiments published in 2006 showed dodder seedlings grow toward airborne chemicals given off by host plants such as tomato, in effect smelling their way to a stem. Later work found dodder and host swapping messenger RNA across the feeding connection, so the parasite is not only drinking sap but exchanging genetic messages; the flax and clover dodders both accounts blamed for ruined fields remain quarantined weeds in many countries.
Written for this edition, 2026.