Monday, April 5, 2010

ID This - A Correct Quiz Answer

I recently posted the following photo as a plant quiz...


Some of the guesses included Boehmeria cylindrica, Urtica dioica (or maybe Laportea canadensis), and Pilea pumila. None of these were correct, but what do they all have in common? They are all in the family Urticaceae. When I first saw this plant, I was convinced it was in the family Urticaceae, but nothing fit. As I was about to give up until I could see a more mature specimen, I thought... man, those leaves look like mulberry. Then it hit me that there was an herbaceous, non-native mulberry that I had never seen. I looked up Fatoua villosa, Mulberry Weed, and sure enough, it was a perfect fit. Interestingly, this species was once known as Urtica villosa.


This is Fatoua villosa, Mulberry Weed, or Hairy Crabweed (Moraceae). It was introduced in the United States from east Asia as recently as the 1960s. First found in Louisiana, it has rapidly spread throughout the southeastern United States, pushing north into Indiana and Ohio; it has also been recorded in California and Washington. Much of its spread has been attributed to the horticultural trade, where it persists as a weed in greenhouses.


In many of the northern locations for this plant, it has been found more commonly inside greenhouses. Only very recently (1991 in Ohio) has this species been observed outside of greenhouses in the northern extent of its range.


Mulberry weed is an annual that continuously produces an abundance of seeds from the time it is a very small plant until it reaches a maximum height of up to 80 cm. When mature, the seeds are "explosively expelled," according to Flora of North America.


Watch for this weed around greenhouses, in waste areas, and in disturbed sites as it continues its northward expansion.

Congratulations, Justin and Susan, for correctly identifying the plant in this plant quiz.

7 comments:

Keith said...

Boehmeria cylindrica, False Nettle.

Scott Namestnik said...

It must be False False Nettle, because it isn't Boehmeria cylindrica.

dguzman said...

True nettle?

Justin Thomas said...

Fatoua villosa.

Cdr said...

Gosh, I don't know what Fatoua villosa is (which doesn't mean much of course) but the photo reminds me of Pilea pumila with those pustules on the upper surface of the leaves. However, I guess it could possibly be Eupatorium rugosum (or Fatoua villosa). It's hard to tell in photo if plant has opposite or alternate leaves (a dirty trick Scott!) but I'm going with opposite..plant does look slightly gray-pubescent which doesn't make sense for PILPUM and doesn't necessarily make sense for EUPRUG....hmmmm..my final answer is Pilea pumila

Susan said...

I concur with Justin... you beat me to it, Justin! Nasty little weed... we used to have it in the Temperate House at the Missouri Botanical Garden. Also had a person bring it in from a yard in Howell County, so it's around...

Scott Namestnik said...

Sorry Keith, dguzman, and Cdr... Justin and Susan have it.