Rusts, Smuts and allies

All images on this website have been taken in Leicestershire and Rutland by NatureSpot members. We welcome new contributions - just register and use the Submit Records form to post your photos. Click on any image below to visit the species page. The RED / AMBER / GREEN dots indicate how easy it is to identify the species - see our Identification Difficulty page for more information. A coloured rating followed by an exclamation mark denotes that different ID difficulties apply to either males and females or to the larvae - see the species page for more detail.

Fungi

Fungi are not plants, as was thought to be so in the past, but in a separate Kingdom of their own. In most cases, the main body of the fungus is hidden from view. It is a network of threads (hyphae) collectively called a 'mycelium', which permeate the substrate on which the fungus grows. The hyphae absorb nutrients and water from the substrate. The reproductive spore-producing structures, such as the familiar mushroom or bracket, are the visible parts of the fungus.

The Fungus Kingdom is extremely diverse, and includes many microfungi that are rarely recorded. Most of the larger species are in one of two major divisions or Phylum, based on the way the fungus reproduces. Basidiomycota (sometimes called 'spore-droppers') include mushrooms and toadstools, brackets, corals, puffballs, jellies, rusts and smuts. The Ascomycota or 'spore-shooters' includes cups, morels, yeasts and many other smaller fungi.

Taxonomy is very complicated and is liable to change as the true relationships between species are worked out. In the sections below, we have grouped fungi into categories based on their structure and appearance rather than their place in the scientific taxonomic hierarchy. There is more information under each section.

Recording fungi

Always note the substrate or host-plant on which the fungus is growing, and the habitat. To identify many large species, it is helpful to get a good photograph of the cap (from the top), the gills or spore-producing structures (from underneath) and the stipe or stem (from the side) - three images from three angles, rather than images from much the same angle.

Always note the texture of cap and stipe; the smell; and the presence of any staining or 'milk' produced when the cap, gills, stipe or body of the fungus is bruised.

The colour of the spores can be very helpful. It is best seen by taking a spore-print from a collected specimen - advice on doing this is in many of the resources below. For some fungi, microscopic examination of the spores may be needed for identification.

Resources

The Leicestershire Fungi Study Group is a great place to start if you want to learn about fungi. They welcome new members. Their annual programme of study forays is led by enthusiastic and knowledgeable leaders. There are also indoor microscopy sessions held in Leicester. This is a really excellent way to broaden your knowledge, and make friends who share your interest in fungi.

There are many field guides, but none of them contain all the fungi you will find, or have all the photos or information you need, so it is a good idea to check several different books and websites.

Courtecuisse, R. & Duhem, B. (1995) Mushrooms and Toadstools of Britain & Europe. Collins
Kibby, G. 2020-2022. Mushrooms and Toadstools of Britain & Europe, Volumes 1 - 4. (privately published)
Laessoe,T. & Petersen,J. (2019) Fungi of Temperate Europe. Princeton University Press, Volumes 1 and 2
O'Reilly, P. (2016). Fascinated by Fungi. First Nature
Phillips, R. (2006). Mushrooms (2^nd edition). Macmillan.
Sterry, P. & Hughes, B. (2009). Complete guide to British Mushrooms and Toadstools. Collins
Wood, E & Dunkelman, J. (2017). Grassland Fungi: a Field Guide. Monmouthshire Meadows Group

Pat O'Reilly's First Nature website has some helpful advice and tips on identifying fungi.

The British Mycological Society website is a good source of information, mostly aimed at the expert.

If you know of other websites or books that you would recommend, do let us know: info@naturespot.co.uk

Rusts, Smuts and allies

In this section are rust, smuts and allied fungi. All are basidiomycetes and plant pathogens, many of them affecting crops and garden plants and causing serious diseases of economic importance.

Taxonomy is difficult and subject to change; the taxonomic hierarchy on the NBN should be referred to.

Rusts usually have orangey or rusty coloured spores. They are currently placed in the Order Pucciniales (formerly Uredinales), with families including Coleosporiaceae, Melampsoraceae, Phragmidiaceae, Pucciniaeae, Puccinastraceae, Raveleniaceae and Uropyxidaceae. Some cause galls. Life histories are complex and many require two host plants in unrelated families to complete their life-cycle - known as the 'primary' and the 'alternate' or 'aecial' host. A classic example is cereal rust (Puccinia graminis), where various grasses including Wheat are the primary host, and Barberry the alternate host. Up to 5 types of spores are produced; a diagrammatic example of a life-cycle is here. In some species, one or more of these spore-types is missed from the cycle, and a few species complete their life-cycles on one host. The 5 spore-types and the structures that bear them are:

Basidiospores forming on basidia on the alternate host plant - these are produced in Spring when over-wintering teliospores germinate. The basidiospores are wind-dispersed, and if they land on the right host they produce a mycelium in the plant tissue.
Spermatia and receptive hyphae borne in spermogonia - tiny haploid spores called 'spermatia' are formed by hyphae near the leaf surface of the alternate host, in spermogonia. Often the spores are in a sweet-smelling matrix exuded by the spermogonia, which is attractive to insects that then carry them to a new host. They may then unite with receptive hyphae in spermogonia on the new host to form a dikaryotic cell.
Aeciospores - spores produced early i the year on the alternate host in cup-like aecia consisting of dikaryotic hyphae. Aecia (singular = aecium) are often orange or rust-coloured; many also cause galls in the host plant. Eventually the spores burst through the roof or 'periderm' of the aecium. The torn remains of the periderm may remain as a whitish fringe around the cup of the aecium (see example). The aeciospores are dispersed by the wind.
Urediniospores borne on uredinia - if the aeciospores land on the right primary host, a different plant species, they germinate. The hyphae invade the host tissue, eventually producing pustules called uredinia, in summer. These are often brown in the Puccinaceae, or yellow/orange in some families. They release the urediniospores; often several cycles of this take place throughout summer spreading the fungus quickly to other plants.
Teliospores borne on telia - in late summer, dark brown or black pustules are produced on the primary host bearing the over-wintering teliospores (see example).

Smuts are characterised by sooty black masses of spores which often replace parts of the flower or grass, or erupt in streaks or lesions on stems. They are currently the order Microbotryales (the family Microbotryaceae), Ustilaginales (e.g. Farysiaceae and Ustilaginaceae) or Urocystidales (e.g. family Urocystidaceae). They have less complex life-cycles; there is no alternation between host plants species, and usually just 2 sorts of spores are produced: basidiospores, or sporidia, and teliospores. The teliospores develop in sori on the anthers, ovaries or swollen stems and leaves of the host, causing a gall. The fungus overwinters as the teliospore, which germinate in Spring to form basidiospores, which then disperse to infect new plants.

The Entylomataceae also produce smut-like spores; some are gall-causing.

This section includes some allied fungi that don't form typical rusts or smuts - the gall-forming Exobasidium; Phleogena faginea, the Fenugreek Stalkball; and the 'living fossil' found on Ginkgo - Bartheletia paradoxa.

To identify some species, spores need to be examined under the microscope. Details of life-cycles, hosts and spore descriptions are on the Bladmineerders website under the host species; this site also covers some of the unresolved taxonomy issues for some species with complex life-cycles. A checklist and guide can be downloaded from Aber University's Waxcap website: https://www.aber.ac.uk/waxcap/links/index.shtml

Henderson, D.M. (2000). A checklist of the Rust Fungi of the British Isles. British Mycological Society

Henderson, D.M. (2004). The Rust Fungi of the British Isles: A guide to identification by their host plants. British Mycological Society