Puccinia graminis is known as stem rust and has influenced cereal farming throughout history. In common with other rust fungi, it is an obligate parasite. This means it needs living host plants to grow and reproduce and without a living host it can only survive as a spore. Thus, rusts make sure to keep their host plant alive. They still cause damage to agriculture, taking nutrients from the plants, causing the infected plants to produce less tillers and thus less seed, which results in loss of yield. There is substantial genetic variation within the species; all “special forms” or formae speciales have an identical apperance but occur on different host ranges.
Puccinia graminis is heteroecious which means that it needs two unrelated host plants to complete its life cycle. Wheat or other cereals are its primary hosts and plants from the barberry family, above all Common Barberry, its alternate host. In addition to alternating between two hosts, Puccinia graminis produces five spore stages. Please read the instructions in the tutorial on how to enter the spore stages in the field life cycle.
The Fungarium at the Royal Botanic Gardens, Kew, houses an estimated 1.25 million dried fungal specimens. It is one of the oldest and largest fungaria worldwide and the most comprehensive in terms of taxonomic and geographic coverage. Funded by the HDH Wills 1965 Charitable Trust, Kew’s Fungarium is currently digitising plant pathogenic fungal species. In the scope of this project, all specimens from Puccinia graminis were digitised. We hold collections of this species from the whole world and all specimens that still need label data captured have been included in this expedition.
Fungal specimen expeditions differ from those of our herbarium specimen expeditions and there are frequently numerous specimens on one sheet. In this expedition you may encounter up to 14 specimens on one sheet. The tutorial explains how to distinguish between specimens and what to transcribe for each task.
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As our Fungarium is based in the British Isles, we store the specimens in divisions within the United Kingdom, e.g. England and Scotland. In addition, we are interested in vice county information for the digital records. The tutorial describes what vice counties are and how to search for the vice county of a given locality.
Image RBG Kew