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Mot de passe perdu? S'inscrire

18-06-2025 19:24

Literature request
Bernard Declercq Bernard Declercq

Good evening,On Oenanthe aquatica we collected  a

18-06-2025 16:24

Anamorphe sur Lycopodium annotinum
Andgelo Mombert Andgelo Mombert

Bonjour,Un minuscule stade imparfait, qui pousse s

13-06-2025 16:34

Strossmayeria-like on Fagus
Andgelo Mombert Andgelo Mombert

Bonjour,Un petit discomycète qui me résiste. Il

11-06-2025 16:26

Literature request
Jason Karakehian Jason Karakehian

Hi everyone, I am looking for the following protol

17-06-2025 14:23

¿Hyaloscypha?
Josep Torres Josep Torres

Hello.A probable Hyaloscypha from last June 1st, s

17-06-2025 12:10

Scutellinia para ID 1303
Castillo Joseba Castillo Joseba

Del pasado dia 4  en bosque de hayas, en tierraA

12-03-2025 17:54

Scutellinia hyperborea?
Karl Soler Kinnerbäck

Hi all!Do you agree with Scutellinia hyperborea? P

17-06-2025 12:02

Scutellinia para ID 2259
Castillo Joseba Castillo Joseba

Del pasado sabado, en bosque de hayas y avellanos,

13-06-2025 09:41

Aquatic ascomycete.
Josep Torres Josep Torres

Hello.A cerebriform ascomycete sprouting scattered

13-06-2025 19:57

Helvella
Castillo Joseba Castillo Joseba

De ayer en bosque de hayas y avellanosEjemplar uni

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Black dots on maple leaf
Alan Rockefeller, 31-12-2013 11:00
Alan RockefellerGrowing on Acer macrophyllum (bigleaf maple).  Seen at the Yuba Watershed Fungus Fair.

No asci observed. Many parathyses with tiny oil drops were seen, they measured 30 – 45 × 2 – 3 micrometers. Many clavate basidia-like things seen, however they never had sterigmata or spores inside. Those measured (28) 36 – 47 x (5) 7 – 8 micrometers.

  • message #26494
Jacky Launoy, 31-12-2013 12:58
Re : Black dots on maple leaf
Rhytisma acerinum (Pers.:Fr.) Fr.
David Malloch, 31-12-2013 15:34
David Malloch
Re : Black dots on maple leaf
Hi Alan..
That is probably Rhytisma punctatum.  The US host-index lists it on Acer macrophyllum in California, Oregon and Washington.  The "clavate, basidia-like things" are probably immature asci.  These would be mature in the spring at about the time the new leaves are emerging on the tree.

Dave
Byrain, 31-12-2013 16:47
Re : Black dots on maple leaf
Alan, I found that leaf and posted it on MO as Rhytisma punctatum.  I have the other two leaves from that collection also.  I scoped them too and also saw no mature asci.

Here are some more macro images... http://mushroomobserver.org/156379?q=1higi?

Edit:  I understand that punctuate dots like this on Acer macrophyllum = R. punctatum, but there is another species with a somewhat similar appearence on other maples.
http://www.glfc.forestry.ca/VLF/ForumPresentations/hsiangtarspot_08e.pdf