Paraisaria gracilis (Grev.) Luangsa-ard, Mongkols. & Samson

Phylum: Ascomycota - Class: Sordariomycetes - Order: Hypocreales - Family: Ophiocordycipitaceae

Distribution - Taxonomic History - Etymology - Identification - Culinary Notes - Reference Sources

This club fungus is parasitic on insects - mainly larvae of various moths, beetles and ants. In this picture, the hosts are larvae of the Swift Moth Hepialus lupulinus.

Description

Parasitising buried larvae (particularly of the Swift Moth) during the spring and summer months, this fungs produces a pale-stemmed club structure with a pear-shaped yellowish-orange head.

Distribution

Rarely recorded in Britain, where it is found mainly in Scotland, this ascomycete species has a world-wide distribution.

Taxonomic history

English mycologist Dr Robert Kaye Greville (1794-1866) first described this club fungus in 1823, giving it the scientific name Xylaria gracilis. In 2019, Luangsa-ard, Mongkols. & Samson renamed it Paraisaria gracilis, which is now its generally-accepted scientific name.

Synonyms of Paraisaria gracilis include Xylaria gracilis Grev., Cordyceps gracillis (Grev.) Durieu & Mont., and Ophiocordyceps gracilis (Grev.) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora.

Etymology

The specific epithet gracilis comes from Latin and means slender.

Identification guide

	Fruitbody 0.5 to 4cm long and 2 to 4mm dia., the fertile head is yellowish orange and pear shaped. The base of the stem is attached to a dead insect pupa below the soil surface. The infertile stem is typically 2.5 to 4cm long and 2 to 5mm diameter.
	Perithecia and asci Close inspection of the surface of the cap of this club fungus reveals tiny raised pores at the tops of spherical perithecia The flask-like perithecia are lined with asci 260 - 600µm long x 3.5-5µm diameter. Within each ascus eight ascospores develop.
	Spores Ascospores are multiseptate (segmented) and filiform (in the form of long threads) eventually breaking into ellipsoidal part-spore segments (rather like a string of sausages), individual part-spore segments measuring 5-9 x 1.5-2µm. Spore print White.
Habitat & Ecological role	In scrubby grassland or on mossy woodland edges, always attached to an insect larva below the ground, often a Swift Moth.
Season	Late spring, summer and autumn.

Culinary Notes

Paraisaria gracilis is not generally considered to have any major culinary value.

Reference Sources

Læssøe, T. & Petersen, J.H. (2019) Fungi of Temperate Europe, Volume 2.

Fascinated by Fungi, 2nd Edition, Pat O'Reilly 2016, reprinted by Coch-y-bonddu Books in 2022.

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi.

Acknowledgements

This page includes pictures kindly contributed by Betty and Tony Rackham.

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