Buffalo Bur Nightshade (Solanum rostratum) x Litchi Tomato (Solanum sysimbriifolium) possible?

Adaptation Projects
,
1

Why does Buffalo Bur Nightshade (Solanum rostratum) look So Similar to Litchi Tomato (Solanum sysimbriifolium)? Are they actually crossable? Both are extremely Close Phylogenically but only Litchi Tomato is known to be Edible, I have no knowledge on Buffalo Bur Nightshade fully ripe fruits being edible (so far it seems not edible even when fully ripe), however I know the plant is toxic especially the Leaves & Green/Unripe Fruits. Plant contains the glycoalkaloid solanine as well as other tropane alkaloids. The plants can also accumulate toxic levels of nitrates from the soil, just like with Lambsquaters or Amaranth. There are also reports of pigs being poisoned by eating the berries and roots. It’s also interesting that Litchi Tomato is also called Red Buffalo Bur, clearly I wasn’t the first to notice their similarity.

What’s also interesting is Carolina Horsenettle (Solanum carolinense) is somewhat Closely Related but in a different clade (It’s closer to eggplants). I know that one isn’t edible & quite toxic, plus the ripe fruits smell disgusting like Vomit & the Calxy doesn’t form a husk to protect the berry.

Look at these Phylogenic Trees

image
image698Ă—444 73.5 KB

Even tho they are sister to each, this Phylogenic Tree shows them in Seperate Clades. This may hint at why 1 is edible & not the other. Seems S. sisymbriifolium is the only species as S. hasslerianum is likely a wild Sub-species of it.

image
image872Ă—205 41.4 KB

image
image750Ă—355 39 KB

Here’s what sparked this idea, just look at how similar these 2 species are.

image
image883Ă—499 53.9 KB

Both seeds have that Bubble/Pitted Texture, often seed morphology indicates relatedness. S. rostratum is black with jagged edges vs S. sysimbriifolium is white with round edges.

image
image801Ă—499 59.2 KB

S. rostratum looks like a more closed-prickly purple/brown Litchi Tomato, vs S. sysimbriifolium is red & has it’s Caylx re-flexed back more.

image
image766Ă—499 43.2 KB

Both flowers look similar, S. rostratum is Yellow vs S. sysimbriifolium is White (Sometimes Pale Blue-Purple)

image
image983Ă—500 102 KB

Leaves also look extremely similar. Both seem to have Prickles on both sides of leaves.

Oh and also for fun, there does actually appear to be a Yellow Phenotype of Litchi Tomato (S. sysimbriifolium). Someone needs to find a way to get those fruits for Litchi Tomato Breeding Experiments. I wonder what it tastes like.

image
image631Ă—606 57.5 KB

Below is the Inaturalist Observation Link

According to this site by Scirpidiella’s Plants, regaurding S. rostratum, she says “…blackish inedible berries completely covered by spiny calyx.”.

And that’s all the info I know about the Close Wild Relatives of Litchi Tomato so far.

2

Oh I should also add both species have the same Chromosome Number n = 24.

Here’s a website comparing the differences between both species.

3

Also known as Kansas Thistle. First time I saw S. rostratum in my yard I was excited because it looked like a watermelon seedling. I still look for watermelon type leaves in order to identify it. It is highly toxic, and I intend to eradicate it entirely if possible.

I have seen it described as “The meanest plant alive,” and that certainly fits among the plants I have met.

Does it have any traits that make it desirable?

4

It really does look like Watermelon leaves. So much so that an extremely closeley related species scientific name is Solanum citrullifolium which means Watermelon-Leaved.

That’s the real question! I posted all this info to see I could get anyone to talk me out of making this hybrid cross. I was wondering why Litchi Tomato doesn’t have many wild species to add more genetic diversity to, that’s how I found out about Buffalo Burr Nightshade.

I was also trying to understand why 1 species was edible & why the others weren’t? I was trying to understand if the toxin is detectable by taste like in the Well Behaved Toxins of the Cucurbitaceae family (Which basically is, if it taste bitter it’s toxic (Except for Bittermelon)).

The only trait I could see that makes it desirable is getting the Brown/Purple color into Litchi Tomato. Otherwise Litchi Tomato is the better plant by all means.

5

My understanding is that the toxin is primarilly solanine, the same toxin that is found in green potatoes. My guess is that none of the toxins are detectable by taste, but there is also the fact that thorns are often a defense for a plant that is a prime edible for something. And boy, does this thing have thorns!

6

Plant contains the glycoalkaloid solanine as well as other tropane alkaloids, however there was no info on how much the fruit contained.

That right there is the scary part! If none are detectable by taste, it’s like playing russian roulette. If so, that makes you appreciate the sacrifices our Human Ancestors have made to test tasting each plant to see if you die or not, but my gut tells me there must’ve been another way to know without dying.

For example From my notes on Potato Berries, “It’s possible that some varieites produce fully ripe Edible Berries, problem there’s no way to know for sure without experimenting on yourself or with Lab Testing for levels of glycoalkoloids. You won’t poison yourself by tasting & spiting them out.” This suggest tasting is a way to test. Unripe Potato berries taste like Unripe Tomatoes. “As they ripen, they become bittersweet, and, when fully ripe and soft, they can become surprisingly tasty, something like a mix of melon and tomato, not that different from a pepino.” - Cultivariable.com

That is a good question, but this is often for parts the plant doesn’t want you to eat like Leaves/roots. Since the only part that’s most often edible for most Solanums are the fully ripe fruit, it’s probably the part the plant wants you to eat. But knowing how the Burs get stuck to Sheep or Animal furs, the edibility might’ve not been a trait too heavily selected for. Also the fact the Buffalo Bur doesn’t open it’s Calxy/husk all the way open suggest it isn’t evolved for animal consumption. Litchi Tomato on the other hand opens all the way making it easy & safe to harvest the fruits without getting pricked, when fully ripe of course. Both are sister to each other, they likely took a different bathway. 1 Sister evolved to be edible as it’s strategy, while the other evolved a hitch hike strategy.

Plants like Stinging Nettle are the prime example of Stings/Thorns being there to protect delicious greens.

7

It was generally a process. Take a single bite, spit it out, wait 24 hours. If your tongue tingles or goes numb, if it tastes nasty, that’s step 1. If no reaction after a day, eat a tiny bite. If no reaction after 24 hours…

And so on. Much of what our ancestors knew was because someone was hungry enough to take a chance, and took the wrong one. Then they teach all future generations not to eat that, although one of their healers might notice peripheral reactions and it becomes a medicine.

8

I don’t know if you have seen one of these other than in pictures. The thorns are hideous, and they cover the whole plant, right down to the soil line, covered with inch long nasty thorns. You can’t approach this thing without getting punctured.

To pull out a mature plant I step on the base, grab it at the base with long handled loppers, pull it out and then burn it.

9

Indeed. I’m thankful for all the humans who thru trial & error found all this info out. Often times the Toxicity is exactly what gives the medicinal value but in a smaller dosage or a different usage.

Never encountered it, only saw pictures & it’s thorns are NASTY!

How do you grab it even with gloves? What does the root system look like? Plus how many of it’s seeds are already in the soil seedbank waiting for the opportunity to germinate in the soil disturbance caused by digging.

10

I don’t try to touch a mature plant. I will bend it back at the base by stepping on it, then pull it out of the ground with a shovel and the loppers or grasp the lower root with gloved hands.

The root system is a single taproot and lots of side roots. I have been here two summers and successfully kept any of these from maturing. However, I do a walkabout the entire property nearly every day watching for this and canada thistle. I nearly always find immature plants, usually when they’re starting to bloom because the yellow stands out.

11

Good, however if keep popping up. There’s a good chance they already have lots of seeds in your soil seedbank waiting for a disturbed soils to germinate again. Do you much those areas? I wouldn’t want to mulch with Buffalo Bur Nightshade, cuz they may still be sharp as they’re composting.

12

Oh, I’m sure it will keep coming. It creeps in from the edges. My usual process is to choose one weed each year. By the end of the season recognition is so ingrained I see it and can remove on my weed tour each morning. So if I get a few a day comong up from the seedbank it’s no big deal to remove them.

I burn the plants.

13

Oh my, do you burn them to make sure the thorns no longer poke you? Or so seeds don’t grow no more?

14

Seeds. If a plant is nasty enough for me to declare total eradication from my yard, I’m not leaving seeds around. That’s two, by the way. Might have been three, but I have been ignoring bindweed in favor of this and Canada Thistle.

1 Like