Hi Jacks

Over the last few weeks, I’ve been working on a plant survey of a local woodland area of about 30 acres. The low, moist areas are filled with Arisaema triphyllum, (Jack-in-the-pulpit) which is quite common in our area. The first image is what is typical for the species.

Arisaema triphyllum Wake County, NC

I’ve been studying patches of Jack-in-the-pulpit for well over 55 years, always looking for unusual leaf forms that showed any type of patterning. Until last month, I’d never found a single form with atypical foliage. That all changed with my first trip to this local site, where so far, I have found several dozen forms with silver leaf vein patterns. Up until now, there are only two pattern leaf forms of Arisaema triphyllum in cultivation, Arisaema ‘Mrs. French’ and Arisaema ‘Starburst’.

Each patterned leaf clone varies slightly as you would expect within a population including both green and purple stalk coloration.

Arisaema triphyllum silver veined clone
Arisaema triphyllum silver veined clone with green stems
Arisaema triphyllum silver veined clone with purple stems

While I’d never found any true variegation prior to this, I had found plenty of transient leaf patterning caused by Jack-in-the-pulpit rust (Uromyces ari triphylli). This site was no exception, with a number of plants showing the characteristic patterning. If you find these, turn the leaf upside down and you’ll see the small orange rust pustules.

While these may seem exciting, the pattern are not genetic and will disappear without the fungus. Fortunately, this rust can be cured by cutting off the top of the plant and discarding it where the spores can not spread via the wind. Infected plant should be fine, albeit smaller next year. The susceptibility of Arisaema triphyllum to jack-in-the-pulpit rust varies with genetics. Of the tens of thousands of plants I observed at the site, less than 10% were infected with the rust.

Arisaema triphyllum with rust induced pattern
Arisaema triphyllum rust induced pattern on leaf back

The devil you say…

Tromping through the woods near the nursery last week and ran across this beautiful example of devil’s urn fungus (Urnula craterium). The original type specimen from which it was named in 1822 was from North Carolina.