The Shaggy Bracket, Inonotus hispidus, is a fungus that produces annual brackets from summer to early autumn on a variety of deciduous trees. I usually see its brackets on Ash trees but they grow on several old Apple trees on our allotment site and the first ones I saw were on Whitebeam trees on a street in Norwich (note 1).
Young and Beautiful
When young and fresh, Inonotus hispidus is a really beautiful fungus, in shades of reddish-orange. Shaggy Bracket oozes liquid as it grows, a phenomenon known as guttation (note 2).
The top of a Shaggy Bracket starts off soft and almost velvety, like the specimen below. If you move your hand across the surface it’s a bit like stroking an animal’s fur. Spores are released from the pores on the lower surface of the fruitbody.
Fresh, young Shaggy Brackets, Inonotus hispidus, on an Ash tree. 24th September 2024.
Ageing Fast
But the brackets soon darken and become more coarsely hairy.
I kept track of a Shaggy Bracket on an old Apple tree on our allotment site this summer. I first noticed it on 6th August.
Shaggy Bracket, Inonotus hispidus, 6th August 2024.
As it grew it flattened out and developed a softly hairy top.
Shaggy Bracket, Inonotus hispidus. 13th August 2024.
After another month (13th September) the bracket was dark on top and had lost its youthful softness (note 3).
Shaggy Bracket, Inonotus hispidus. 13th September 2024.
A fortnight later it had darkened still further, but looked lovely after rain (the cause of the drops underneath, rather than guttation).
Shaggy Bracket, Inonotus hispidus. 26th September 2024
By late autumn Shaggy Brackets have become dry and blackened. The top surface now resembles a disreputable old rug.
The first Shaggy Brackets I saw looked like this and when I saw my first young specimen a year or two later I was surprised at the difference in appearance and texture.
Old Shaggy Brackets, Inonotus hispidus, on a Whitebeam trunk. November 2019.
Shaggy Brackets remain on their host tree in the winter but eventually they fall to the ground. I sometimes find them on road verges when out on a walk or bike ride, usually beneath an Ash tree.
Fallen brackets can survive for a considerable time and I still have an old fruitbody from summer 2022. It is on the ground in a corner of my allotment and provides shelter for a family of woodlice and a Leopard Slug.
Old, fallen Shaggy Brackets on the ground beneath an Ash tree.
White Rot
Unfortunately for the host tree, Inonotus hispidus causes a white rot in the trunk, simultaneously breaking down cellulose, hemicellulose and lignin, sometimes preceded by a “soft-rot” phase, a local breakdown of cell walls. The Newcastle Tree services website calls Shaggy Bracket “a slow assassin”.
The severity of the damage will depend on the tree. Branches of Ash trees (Fraxinus) often snap or break and trees have to be felled if there is danger to passers by, but Plane trees (Platanus) are more resilient and branches are less likely to fall, even when hollowed out.
The bracket’s attachment point on the tree trunk often remains darkened after the bracket has fallen. A sunken canker, caused by destruction of cambium, can form beneath the bracket, as shown in a photograph on the TMA Services website.
Inonotus hispidus may not fruit every year so clues like fallen brackets and darkened areas on tree trunks and branches can provide valuable clues to arborists inspecting trees to assess their health and safety (note 4).
Shaggy Bracket fruitbodies usually grow from quite high up the trunk or on the upper branches of the tree and this is the part of the tree that rots. However, last week I found a Shaggy Bracket at the base of an Ash tree, presumably growing from where the tree had been damaged by someone cutting the roadside verge.
Shaggy Bracket, Inonotus hispidus, growing at the base of an Ash tree. 14th September 2024.
Confusion Unlikely
The Wild Food website describes Inonotus hispidus as “almost unmistakable when young, but when its is dry, there are a few possible confusions”. The two most likely are:
- Chaga, the sterile sclerotium (conk) of Shaggy Bracket’s relative Inonotus obliquus. It usually grows on Birch (Betula) trees and is rare in England but more common in Scotland. The inside is reddish brown when cut but it doesn’t have the tubes and pores of the Shaggy Bracket’s fruitbody.
- An old and dry fruitbody of Dyer’s Mazegill (Phaeolus schweinitzii). This does have tubes and pores but normally has a noticeable stem. Dyer’s Mazegill is primarily a root parasite of conifers and is rarely found on broadleaved trees.
I have never needed to check any microscopic features of Inonotus hispidus but the First Nature website gives details of pores, tubes and spores and the book ‘Poroid Fungi of Europe’ (note 1) has many more details. The First Nature and Nature Spot websites have more photographs of Shaggy Bracket fruitbodies.
“Shaggy Fibrous Ear”
The generic name Inonotus comes from ino– (fibrous) and ot (an ear). The specific name hispidus comes from Latin and means stiffly hairy, shaggy or spiny. Alternative English names include Shaggy Polypore, Velvet Fungus and, in the United States, Inonotus Canker.
In the British Isles, Inonotus hispidus is widespread and common in England but scarcer in Ireland, Wales and Scotland. It is common in south-western and central Europe and southern Scandinavia and can be found in many parts of Asia and North America.
The Shaggy Bracket isn’t an edible fungus – it’s just too tough. But it’s a lovely sight to behold, even if its growth can have unfortunate consequences for the host tree.
Notes
Note 1 – In ‘Poroid Fungi of Europe’ Ryvarden and Melo give oaks (mainly Quercus robur and Quercus petraea) as the main host trees in southern and central Europe. Other deciduous hosts are Apple (Malus, particularly on the Iberian peninsula), Sweet Chestnut (Castanea), Beech (Fagus) and Pear (Pyrus, in Sweden). In North America and former Yugoslavia Abies (fir trees) are the preferred host. L. Ryvarden & I. Melo (2022). ‘Poroid Fungi of Europe’. 3rd edition. Fungiflora, Oslo, Norway.
In the UK, Ash (Fraxinus excelsior) and Plane (Platanus) are major hosts and Walnut (Juglans), Whitebeam and its relatives (Sorbus) and Sycamore (Acer pseudoplatanus) are also used. Guy Watson & Ted Green (2011). ‘Fungi on Trees: An Arborists’ Field Guide’. Arboricultural Association, Stonehouse, Gloucestershire.
Note 2 – Like its relative the Oak Bracket, Pseudoinonotus dryadeus, that I wrote about in October 2021.
Note 3 – This is the stage of development shown in the Sterry and Hughes’ book ‘Collins Complete British Mushrooms and Toadstools’.
Note 4 – On our allotment site fruitbodies appeared in the summer of 2022 but then skipped a year and more were produced this summer.
