This section is from the book "Sub-Alpine Plants Or Flowers Of The Swiss Woods And Meadows", by H. Stuart Thompson. Also available from Amazon: Sub-Alpine Plants: Or, Flowers of the Swiss Woods and Meadows.
Twining or prostrate herbs, with alternate leaves, or leafless and parasitical (Cuscuta). Calyx of 4 or 5 sepals often very unequal. Corolla usually campanulate, with 4 or 5 lobes or nearly entire. Stamens 4 or 5, attached near the base of the corolla. Partitions of the capsule very thin.
The family is not represented in Alpine regions properly so-called, but in the lower mountains of Europe Cuscuta or Dodder is frequently seen.
An annual parasitical, leafless plant, with twining, thread-like reddish stems, which attach themselves to Thyme, Heath, Gorse, and other shrubby plants by means of minute suckers. The heads of flowers are small, globular, and compact, the flowers themselves being very small, white or pale pink, and the calyx still smaller. Corolla-lobes pointed, spreading, and about as long as the tube. Capsule globular, with 4 seeds in 2 cells.
Parasitical upon various plants in sunny places in the plains and Alps to at least 6000 feet. July to October.
In Europe from Denmark southward, N. Africa, W. Asia. British.
Dodder was observed by the author during the hot summer of 1911 in unusual abundance in the Pennine Alps and upon a variety of plants, such as Euphorbia Cyparissias, Carduus defloratus, and Teucrium montanum. He also found it actually parasitical upon two fronds of Polypodium Robertianum, which is perhaps the first record of any kind of Cuscuta upon a fern; 1 though, according to Prillieux, Rye-grass has been attacked by C. Epithymum. It is also occasionally found on Lotus corniculatus, Lavender, and other Labiates, Hypericum and Achillea millefolium. When Dodder grows on Clover, or Lucerne, which it often does in the sub-Alps, as in England, the name C. Trifolii Bab. is given to the variety. It differs from the type in its shorter distant scales. Several other species of Cuscuta are occasionally found in the lower mountains of Southern Europe, but they are difficult to determine, and it is hardly within the scope of this book to attempt to describe them here.