Diderma floriforme(Bull.) Pers.

This page was originally titled Lepidoderma stipitatum Flatau. In a recent paper Ronikier et al. (2022) clearly demonstrates that L. stipitatum represents malformed Diderma floriforme sporcarps, only deviating in peridial characters; Based on DNA sequence data the two taxa are identical.

Persoon, C. H. (1794) Neues Magazin für die Botanik 1: 89
Type loc.: France.
MycoBank #205206

Lepidoderma stipitatum Flatau
Flatau, Leo 1984: Z. Mykol. 49(2): 179-182
Type loc.: Germany, Hessen, Reinhardswald.
MycoBank #103522

globose sporocarps, gregarious, 0.6-07 mm Ø, stipitate. total height 2 mm, brownish beige, shining.

membranous, continuos under a group of sporocarps, greyish yellow by TL.

2/3 of total height, furrowed, often ± flattened and somewhat twisted, brownish beige and ± translucent by RL, yellowish orange and translucent by TL.

reddish brown, slightly rougehed, 1/3 of sporocyst diam.

rather tough, pale greyish yellow by TL, irregularly roughened on the inside, on outside with numerous flattened lime scales, pale greysih yellow by TL, and with a faint internal radiating pattern, 15-30 µm in diam.

of thin, 1-1.5 µm broad, dark brown threads, pale at extremities, radiating from columella to peridium, sparsely branched at narrow angles, with irregular warts along whole length exept at extremities.

globose of somewhat ovoid, 8.5 - 9.2 - 10.0 µm Ø (n=25), medium to dark brown by TL, often paler on one side, almost black by RL, with scattered, large spines up to ca 1 µm high, and occasionally with a few ridges.

The danish specimen was found on the inside of large piece of Quercus bark. The German finds were made on dead wood af Fagus and Carpinus.

Distribution in Denmark
So far only one find: Sjælland, Hornsherred, Jægerspris Nordskov.

Global distribution
L. stipitatum has only been published from two collections in Germany, Hessen. See Flatau, Leo 1984.

The Danish specimen was collected and identified by the late Svend Olsen. Svend was a keen and talented amateur mycologist. At his death in 2013 he left a collection of myxomycetes of allmost 400 specimens, of which many rare species and some new to Denmark. An obituary was published in "Svampe" vol. 68, the periodical of the Danish Mycological Society.

The present collection deviates in some minor respects from Flatau's description of the type. The stipe of the Danish material is completely devoid of lime inclusions and translucent by TL. The spores are beset with scattered, medium sized spines, not warts, although Flatau describes the warts as "kurze konische Stacheln".

In 2019 I wrote:
"In microscopical characters L. stipitatum bears some resemblance to Diderma floriforme, which have prompted Poulain et al., 2011 to suggest that "This species might be a lepidodermoid form of Diderma floriforme". I do not agree."
Based on the new information, I must admit, that I was wrong. Once again, the taxonomic jugdement of Marianne Meyer and collaborators turned out to be true.

Description and discussion based on the only Danish collection: SAAO 357, Denmark, Jægerspris Nordskov, 6.5.2002, on bark of Quercus.


Abbreviations: TL : transmitted light; RL : reflected light; Ø : diameter; TBU : Danish Botanical Topographical District.

Colour-codes refer to: Kornerup, A. & J. H. Wanscher 1974: Farver i farver. 5th reprint. Politikens Forlag, Copenhagen.

When not otherwise indicated spore measurements are given as: min-mean-max or (extreme-)min-mean-max(-extreme). Spore measurements are exclusive of ornamentation.

Line drawings are free hand sketches.

Distribution maps: Maps of Danish distributions are based on material seen by the author. World distributions are based on reports extracted from literature.

Diderma floriforme:
Diderma floriforme (Bull.) Pers. - Sporocarps
Sporocarps (hfg2450)
Diderma floriforme (Bull.) Pers. - Fragment of capillitium
Sporocarps (hfg2450)
Diderma floriforme (Bull.) Pers. - Peridial scales of deviating form
Sporocarps (hfg2450)
Diderma floriforme (Bull.) Pers. - Spores (upper: surface view, lower: optical section)
Sporocarps (hfg2450)