Arum italicum Mill.
United States, New York, Bronx, Bronx, NY, USA
Herb forming dense circular patch, the plants densely crowded, the stems erect from deeply buried corms; the corms blackish outside and white inside; plants apparently dividing by production of ovoid daughter corms ca 1 cm diam; lower stems white where buried; petioles purplish at gound level, then green; leaf blades dark green with whitish veins. This patch has been here for at least since 2013. It has slowly grown in size. Now it is forming satellite plants about two meters away from the main patch. These plants are spontaneous here. Voucher number 15915, NY. The patch pictured here was about 40 cm diameter. Pictured in the background, upper left under the split rail fence one can see a couple more plants emerging. I believe these satellite plants have appeared in the last few years. The corms appear to be contractile, as the largest corms are the deepest. Note the bulbils in my hand. They are produced directly off the corms (see picture). These are just a few of the hundreds or perhaps thousands that are under this one 40 cm diam patch. This patch may have spread from the Rock Garden planting about 100 meters west. The corms, bulbils or seeds may have been spread by rodents. The plants could also be spread by movement of soil contaminated with corms, seed or bulbils. After handling the plants for these photos and for the herbarium voucher on the afternoon of Feb 24, my hands were burning slightly. That lasted a few hours. 24 hours later, the symptoms were about the same. 48 and 72 hours later (Feb 28), my hands began itching very badly as though exposed to Poison Ivy. There are small welts and my hands burn slightly. I can't say unequivocally that these symptoms are from the Arum. I could have handled Poison Ivy, but I did not see any near the Arum plants, so that is doubtful. On Feb 28, I rubbed some corm and stem juice from a Manhattan plant on an unexposed, protected part of my forearm to see what happens. As of 3 March, there is no sign of irritation.
Record ID: 7bad8271-9e72-4eef-af69-973543102eb1