Entyloma corydali ex Corydalis solida Lohrsdorf, RLP, Germany, 6.4.2026 #Brandpilz #Smutfungus #Phytopathology #FungiFriends

Weer een Thlaspi alliaceum, dit keer in een boomspiegel in Zuilen, Utrecht

We sequenced the genome of 'desert ginseng' (Cistanche deserticola) - a leafless parasitic plant that gave up photosynthesis - and found it lost huge chunks of its own genome…but started stealing genes from its host! Thanks to my collaborators Prof Huang + her talented team👏🏻 lnkd.in/evF5iU9G

The fact that Americans thought Auxin was a “Hoax from Europe” rightfully got some attention in my latest #PlantScienceClassics post. But it’s actually even funnier if you learn about the context & consequence of White speaking these words to Went at the AAAS Meeting in Pittsburgh. #PlantScience 🧪 🧵

The Biodiversity Heritage Library is turning 20! 🎉 We’re starting celebrations with a special anniversary blog series #BHLat20: Treasures from BHL, featuring remarkable works chosen by the people who know them best: blog.biodiversitylibrary.org/2026/03/cele... #ILoveBHL

Phragmidium sanguisorbae (Kleine-pimpernelroest in Dutch) on Poterium sanguisorba (Kleine pimpernel). Multicelled dark teliospores, 60-70 um in length. Found this weekend in the Kennemerduinen near Haarlem (NL). #fungifriends #rustfungi

🎉 Huge news for BHL: The Field Museum is taking over the hosting of BHL’s website, servers & infrastructure, ensuring long-term stability and access for its 63+ million pages of open biodiversity literature. Learn more: blog.biodiversitylibrary.org/2026/02/tran... #BHLTransition #ILoveBHL 🌍 📚 🧪

A bit of sun yesterday and Mibora minima (dwerggras) flowering in the dunes of South Holland. Today it snowed again. No spring yet.

The EU will #GiveGenesAChance! 🇪🇺💚 www.europarl.europa.eu/news/en/pres... #Trilogue #NGTs

Puccinia silai ex Silaum silaus #Silaumsilaus #Silaum #GewöhnlicheWiesensilge #peppersaxifrage #Cumindesprés #Pucciniasilai #Puccinia #Phytopathology #Rustfungus #Rostpilz #mushroom #mushrooms #fungus #fungi #pilz #pilze #champignons #champignon #nature #natur #FungiFriends

Puccinia carniolica ex Dichoropetalum carvifolia #Dichoropetalumcarvifolia #Dichoropetalum #KümmelHaarstrang #Pucciniacarniolica #Puccinia #Rostpilz #Rustfungus #mushroom #mushrooms #fungus #fungi #pilz #pilze #champignons #champignon #nature #natur #FungiFriends #Phytopathology

Yet another case of Uromyces plumbarius on Oenothera lindheimeri (Gaura) in the Paris region. #Rust #RustFungus #UrbanPlantHealth #PlantHealthDay @wheatpath.bsky.social @erikslootweg.bsky.social www.biorxiv.org/content/10.1...

Net verschenen in natuurtijdschriften. Ons 15-jarig onderzoek naar woladventieven langs de Grensmaas. natuurtijdschriften.nl/pub/1030013/...

The rust Puccinia thlaspeos on Noccaea caerulescens. The rust infection changes the morphology of the plant; instead of flowering stems its stems are full of yellowish leaves covered with telea on the underside. Here on soil heavily contaminated with heavy metals in Kelmis, Belgium.

Happy to share this preprint confirming "Uromyces plumbarius first reported on Oenothera lindheimeri in Europe with widespread distribution and association with the rust hyperparasite Sphaerellopsis sp." Thanks @pascal-frey.bsky.social & @erikslootweg.bsky.social! doi.org/10.1101/2025...

Urocystis eranthidis ex Eranthis hyemalis #Urocystiseranthidis #Urocystis #Eranthishyemalis #Eranthis #Winterling #winteraconite #Eranthedhiver #pièdigallo #Brandpilz #smutfungus #Brand #smut #Pilz #fungus #phytopathology #nature #FungiFriends

found two Claviceps-parasitising fungi on the same plant in September this year. Fusarium heterosporum which colors the whole Claviceps sclerotium orange was the second. It has nice banana-shaped 3-septate conidia. #fungifriends

Epicoccum andropogonis, a fungus parasitising Claviceps, a fungal parasite of grasses. Here on Glyceria maxima (Liesgras). One of two Claviceps parasites I found this day in September this year on the same plant. I really like the brainlike structure (and its old name Cerebella). #Fungifriends

Ragnhildiana ferruginea ( www.mycobank.org/page/Name%20... ) on Artemisia vulgaris (Bijvoet). Common, but underrecorded in the Netherlands. Forms brown fuzzy spots on the underside of the leaves. Conidiospores light brown and mostly 1-3 septate.

Ter afsluiting: Kortsteelgalmug in 25 kmhokken. Van zeer zeldzaam naar zeldzaam.

A nice splash of color of the ascomycete Aleuria aurantia (grote oranje bekerzwam in Dutch) on a cloudy day last week. #fungi

Now is the time to look for Melampsoridium carpini (Haagbeukroest) on Carpinus betulus (Haagbeuk); the bright orange spores stand out on the fallen leaves. Until recently not known in the Netherlands, but in the last 2 years seen at 4-5 locations. These were found in Doorwerth, close to Arnhem.

Tilletia menieri on Phalaris arundinaceae (rietgras). Surprisingly smelly smut fungus with good looking spores. Near Tiel, the Netherlands. #wildplantdisease

Hyalopsora polypodii (blaasvarenroest in Dutch) on the fern Cystopteris fragilis. Found it in a botanical garden. This fern is quite rare here in the Netherlands, and this is the first time I saw this nice orange rust.

Telia of Puccinia chrysosplenii (goudveilroest) on Chrysosplenium oppositifolium (paarbladig goudveil), near Nijmegen. Have been looking for this species for some time. Glad that @NielsEimers discovered it a few weeks ago. #rustfungi #wildplantdisease

Mycocentrospora acerina on Impatiens glandulifera. Found in a wet and shady riparian forest along the Oude Maas, south of Rotterdam. #wildplantdisease

Nog een vindplek van Thlaspi alliaceum erbij. Dit keer in een slootkant in Kesteren naast een bomenkweker met ook weer een rijtje beuken. (lookkrodde zou een aardige Nederlandse naam zijn). 4e hok in de Betuwe, 7e in NL.

The impressive aecia of Puccinia minutissima on swamp loosestrife (Decodon verticillatus) near Waterloo in Michigan. The story of how the life stages of this rust on swamp loosestrife and sedges were linked is described here: ...

Teliospores of Allodus podophylli, Mayapple rust. Nice find during a recent visit to Michigan.

Endoconospora cerastii (I think) on Cerastium vulgare near Ede (NL). Thought for a moment that I found Phacellium alborosellum, but this looks very different under the microscope. #wildplantdisease

The smut fungus Farysia thuemenii (Zegge-urntjesbrand) in the fruits of the sedge Carex riparia (oeverzegge), a few weeks ago near Arnhem. The spores are 6-7 um in diameter.

The smut fungus Urocystis trientalis on Trientalis europaea. Near the Dörenther Klippen in Germany.

A beautiful slime mold from last weekend; Arcyria denudata (Karmijnrood netwatje in het Nederlands). Fruiting bodies on a rotting tree trunk with spores in an intricate net-like structure. #myxomycete

Telia (dark) and uredinia (lighter brown) of Puccinia sorghi on maize in the local allotment gardens today. Microscopic image of the two-celled teliospores. #rustfungus

Another smut fungus; Rhamphospora nymphaeae in the leaves of a waterlily in a garden pond. Neat colorless spores that look like little eggs. #smutfungus #wildplantdisease

Another smut fungus I found yesterday; Ustilago trichophora forming large galls filled with masses of small (8-10 um) brown spores on the stems of the grass Echinochloa crus-galli.

The smut fungus Microbotryum cordae on Persicaria hydropiper (waterpeper, water-pepper). Small hydrophobic spores with a beautiful net-like structure fill what used to be the flower.

The rust Puccinia cribrata on Vinca minor. The infected parts of the plant grow taller, which helps the rust fungus spread its spores. Found it near our allotment garden in Wageningen. Might be new for the Netherlands. #rustfungus

Miricatena prunicola on Prunus serotina was in 2011 described in the UK: Kew Bulletin 66:637-642. I am surprised how widespread this fungus is in the Netherlands. I never noticed it before and this year I see it everywhere. Its host was introduced here more than a century ago.

Teliosporen van Gladde roosroest (Phragmidium rosae-pimpinellifoliae), nu te vinden op Duinroos (Rosa spinosissima). Erg onopvallende plukjes sporen aan de onderzijde van het blad. Eerder in het jaar vallen de fel oranje aecia meer op. Nationaal Park Zuid-Kennemerland.

Telia van Aspergeroest (Puccinia asparagi) op Asperge (Asparagus officinalis). Net over de grens in Duitsland tussen de rivierduinen van de Wisseler Dünen. In Nederland wordt deze roest zelden gezien. #wildplantdisease

Heelblaadjes-rusroest (Uromyces junci) op Paddenrus (Juncus subnodulosus). Dit zijn de teliosporen. Gisteren gevonden in de Middelduinen bij Ouddorp. In Nederland is dit vooral een soort van de kust; https://www.verspreidingsatlas.nl/2022150 #wildplantdisease

Volkstuintjes zijn altijd interessant wanneer je plant-parasitaire schimmeltjes zoekt. Hier bonenroest (Uromyces appendiculatus) op een slaboon (Phaseolus vulgaris). Eencellige teliosporen. Ik ben deze dit jaar meer tegengekomen dan in voorgaande jaren.

Bezoekje aan de botanische tuin in Utrecht afgelopen week. Prachtige planten en ook wat mooie roesten waaronder Irisroest (Puccinia iridis) op Florentijnse lis (Iris germanica 'Florentina'). De wand van de topcel van de teliosporen is opvallend dik.

Fijnspar-prunusroest (Pucciniastrum areolatum) is nu goed te zien op Vogelkers (Prunus padus). De geinfecteerde delen van het blad verkleuren fraai geel en rood. De uredinia bevinden zich aan de onderzijde van het blad.

Mispelrotkelkje (Monilinia mespili) op Mispel (Mespilus germanicus). Dit is het asexuele stadium met conidiosporen in lange ketens. Het sexuele stadium met asci volgt na de winter op de resten geinfecteerde mispels.

Uredinia van de roest Puccinia maculosa op de onderzijde van het blad van Muursla (Mycelis muralis). De geinfecteerde planten vielen op door de gele vlekjes aan de bovenzijde van het blad. De sporen van de roest hebben prachtige papillen over hun kiemporen.

Gestekelde rietgrasbrand (Ustilago echinata) op Rietgras (Phalaris arundinacea) in natuurgebied de Mortelen. Deze brand heeft opvallend grote gestekelde sporen. #brandschimmel #smutfungus

Massaal Koekoeksbloemmeeldraadbrand (Microbotryum lychnidis-dioicae) op Avondkoekoeksbloem (Silene latifolium subsp. alba) bij Lathum. De kleine (ca 7 um) sporen hebben een prachtig netvormig patroon.