To make up for some of my recent extra-long posts, here’s one that’s short and sweet… If something involving rhubarb can be called sweet.
The vast majority of email queries I receive are along the lines of, “here’s something I wondered about and I figured it was easier to just ask you than look it up in your book.” But every once in a while, I get one in the form of, “I found this weird thing I’ve never seen before, and I couldn’t find anything like it in your book or in the whole internet!” The latter type is of course more interesting to me, but sometimes I can’t do much to help besides put the thing on the internet and see what happens. So here goes.
Yesterday David Gregg of the Rhode Island Natural History Survey found this thing growing out of the midrib of a rhubarb leaf at his house:
I’m thinking that if there were a regularly occurring gall on a common garden plant like rhubarb, it would be well documented. So I suspect this is some kind of freak mutation. The thing at the end of the “string” coming out the middle of the “satellite dish” looks vaguely like the winged fruit of rhubarb, so maybe this one part of the plant just got some mixed genetic signals? Has anyone seen something like this before, or does anyone have anything more intelligent to say about it?
BugTracks 
Aliens built it to “phone home”
Check out the houseplant Tolmiea menzieslii — the piggyback plant. Perhaps a similar mutation has occurred in the rubarb!
Wow! Chris has a good idea. I wonder what else will come up to explain this?
Well here’s something:
And also: https://twitter.com/colinpurrington/status/1269994649013215233
Hi — I received this reply from a botanist I know at Missouri Botanical Garden. I’m sure you will find this clarifies the situation considerably… (um, well, that is, I mean, sort of…🤔..)
Jan Beckert
“That is indeed remarkable, and I certainly haven’t seen it on any of the rhubarb I have eaten… So there are various levels to this. If you think of Nepenthes and Sarracenia, they have leaves that are formed in a basically similar way – the adaxial/upper side of the leaf forms a tube/pitcher (= epiascidiate!!). But something that looks more like the rhubarb can be found in some cultivars of Croton (= Codiaeum), where you get structures forming from the midrib of the leaf; sometimes they are just projections, but they can also be more or less peltate (= umbrella-like) and bear similar structures in turn, quite like the structures here. Liberty Hyde Bailey talks about them in his “Standard Cyclopedia of Horticulture”. But why/how do they form? They could be some sort of gall, but the rhubarb doesn’t look like that, or they could be formed as the result of some change at the genetic level.”
Oops, forgot to append his name; it is Peter F. Stevens at Missouri Botanical Garden.