Rampant Rust

This is Alexanders Smyrnium olusatrum flowering near Tynemouth castle at the mouth of the river Tyne, in May. At this time of year the flowers have yet to appear but there is a lot of lush growth in its glossy leaves. The plant is supposed to have been introduced as a pot herb by the Romans and it was widely grown as a spring vegetable for its edible stems and leaves for centuries, until it was replaced by celery . The feral populations that are frequently seen are usually the result of past cultivation.

One of the reasons why it may have fallen out of favour might be this rust fungus, Puccinia smyrnii. It distorts the leaves, causing them to swell, then erupts through the surface and releases spores before they wither. Many of the plants that we saw around Tynemouth castle today were heavily infected.

If I'd been a gardener, growing this plant in my kitchen garden, I'd be very disheartened.

More rust fungi here and here

Rusty nettles

The recent warm, humid weather has provided excellent conditions for the development of stinging nettle rust fungus Puccinia urticata and there are some colourful infestations on our local nettle patches.

The disease tends to produced flattened, distorted stems and also .....

... patches of spore cups on the underside of the leaves. 

For a close-up view of the spore cups and their contents in a related species of rust fungus, click here.

Season of Mouldy Fruitfulness

A few days of mild, humid weather has produced some fine displays of moulds and rust fungi on fruits and leaves that are reaching the end of their useful lives. This bramble is afflicted with both diseases – Botrytis mould consuming its rotting fruit and the rust fungus Phragmidium violaceum producing some beautifully colourful effects on its ageing foliage. There’s a peculiar kind of beauty to be found in decay.

Pristine bramble fruits, before Botrytis fungus found them.....