6323fa3e21c656bd508063bfe72d8d82

2012-05-13 Vienna XXII. district, Lobau - Danube National Park German name: Nessel-Teufelszwirn (Nessel-Seide), auf Ruderal-Trespe This is a very untypical combination of parasite and host plant: Cuscuta europaea usually prefers Urtica, Humulus, Salix, Alnus and other species; here it is inserting their haustoria into Bromus sterilis, an annual or biennial grass on which in all likelihood it won't reach flowering status, and by no means it will produce there if it can't find one Urtica dioica or Solidago gigantea to nurture itself (both of which are ubiquitous in this habitat, so it is perfectly possible that it will still reach a plant which could sustain its needs). This Cuscuta specimen is still very young, and hard to discover at this stage of development; they won't flower before june. Last year I observed in the very same place numerous Cuscuta specimen killing many Bromus stalks (as said, they just can't sustain the needs of this greedy parasite) but plenty of them survived on Urtica and Solidago. Very small Cuscuta specimen even can "crawl" on earth: they grow on their top, using up substance at the end of their shoot - which is their strategy of finding a host, which also could be an inappropriate one like is the case here. They only have very small quantities of chlorophyll - but unlike many other parasites they have at least some, possibly to sustain them through their critical germination period before finding a host? - and thus hardly produce any energy of their own, as "ordinary" plants would do.