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NEYEDC improve and inform environmental decision making, conservation, land management and sustainable development in North and East Yorkshire through the collation, management, analysis and dissemination of biodiversity information.

The Natural History of Yorkshire in 100 Species

Explore the rich and diverse natural history of our region through the stories of 100 species, told by the people who know them best.

#80 Green Earthtongue by Mal Greaves

Meet Mal Greaves, mycologist!

Mal has been fascinated by fungi in all their guises for over 40 years. With no formal background in this enthralling field, his journey has been long, exciting, yet often testing and frustrating. While his interest spans all fungi, his first focus was on species with large fruiting bodies, such as the Boletes. From there, he transitioned to the smaller-fruiting Mycena.

To sustain his studies during the off-season, Mal then turned to fungi growing on herbivore dung, which can be observed year-round. This exploration led him to delve into a specific group, the Scutellinia or Eyelash fungi, for which he has developed an online key to help others identify their own finds.

Mal’s current obsession lies with the CHEGD+ group, especially the Earthtongues. While some other species in this group are highlighted in other 100 Species blogs, Earthtongues often feel like the poor relations within the CHEGD+ family, as they are challenging to spot and can be even harder to identify. Like most the other members of this group, they tend to grow in uncultivated ‘poor quality’ grassland in the UK. Interestingly, they are more prevalent in woodland in the USA.

In the field the Earthtongues can usually be split into 4 groups. Most are black and if they have small hairs on the stem and fertile head, best seen with a hand lens, they belong to the Trichoglossum group. If they have a sticky stem, they are likely to be a Glutinoglossum. The majority of the rest are Geoglossum. We then have the ones that come in shades of brown, green, and even purple - and this brings us to the genus Microglossum.

Microglossum viride

Microglossum is a fascinating genus in the family Geoglossaceae, collectively referred to as Earthtongues due to their slender, tongue-like fruiting bodies. Though typically small and understated, these fungi play a vital role in decomposing organic matter and cycling nutrients in soil ecosystems, with some of them also being an indicator of threatened grassland habitats. Whilst the grasslands they appear in look ‘poor quality’ – often lacking interesting floral diversity, by which the quality of many other grassland type habitats and designation of sites is often judged – these seemingly unimportant habitats are actually increasingly rare in the UK. These habitats are unimproved; they have not been ploughed, seeded, or heavily fertilised. In the UK, unimproved neutral grassland declined in area by 95% in the 20th Century due to changes in agricultural practice and this trend continues. Today, it is estimated that there is less than 15,000ha of this habitat remaining in the UK. Searching for and recording CHEGD species, including Earthtongues, is an excellent way to identify these habitats, judge their quality, and, in some cases, help them be protected by local and national legislation. NEYEDC’s Waxcaps project, which formally ended in Autumn 2024, set out to do just this: Waxcaps — neyedc.

Among the most remarkable members of the Microglossum genus are the green Microglossum species, such as Microglossum viride, or the Green Earthtongue. This species is especially striking due to its vibrant green coloration, caused by pigments like chlorociborin. Found in mossy or grassy habitats, M. viride often thrives in nutrient-rich soils and typically emerges in late summer to autumn. Its preference for woodland habitats, however, excludes this species from the CHEGD group, which is more focused on grassland species.

The green Microglossums are not only visually unique but also ecologically significant. They occupy a distinct niche in their ecosystems and can serve as indicators of healthy, undisturbed environments within grasslands and beyond. Unfortunately, due to habitat loss and environmental changes, some species have become rare and are now of conservation concern in their own right.

Until relatively recently, all the non-black grassland species were lumped together as Microglossum olivaceum, whatever their colour. In 2017 they were split via DNA sequencing and physical characters and were allocated individual names. Among this green/brown group, Mal’s personal favourite is Microglossum tenebrosum, a rarely recorded species with only a handful of known sites in the UK. It grows singly or in small groups. Its small fruiting body reaches up to 2” tall and has a pale green stem with a slightly darker and pointed fertile head. Its elusive nature, due to its size and the habitats it favours, adds to the allure of studying this incredible genus. As it grows in grassland it is often difficult to spot. Mal first found this species in a disused chalk quarry in East Yorkshire, and it has reappeared on a few occasions since.

Recording and monitoring

Records of CHEGD fungi species within Yorkshire can be sent to your relevant LERC, or uploaded to iRecord where they can be verified before becoming accessible to your LERC. Whilst the Waxcaps project has formally ended, NEYEDC are still involved in the recording and mapping of fungi in Yorkshire – keep your eyes peeled for future work.

Further information and acknowledgements

NEYEDC would like to thank Mal for his time and expertise in helping to create this blog.

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