weeeeds everywhere, man

I'm always coming across this weed in the city- it seems to grow everywhere. Its striking purple and yellow flowers would grab anyone's attention (anyone who has a tendency to look at weeds in the first place, I guess) and they always seemed awfully familiar to me, like some shunned trailer trash 2nd cousin of potato, pepper, and tomato plants. The flowers are almost identical in shape to yellow tomato flowers, and though the leaves really aren't, their shape and surface really do resemble a cross between potato and pepper leaves. At some point a long time ago, I read that tomatoes (and peppers) are related to deadly nightshade, and that for a long time a lot of people didn't eat tomatoes because other nightshade plants are poisonous, fruit and all. Tomato leaves and stems are poisonous, in fact, even though they smell so good. So for a long time I've assumed these things were in the nightshade family, but never looked to confirm. Last week, in a fit of relative productivity, I brought out my camera and took a picture of one of these plants (among other things) on one of the streets in my running route and I finally took the time to look them up. There are lots of plants and animals that look very similar but are only distantly related, but in this case I was happy to find that I was pretty much right on - the purple flower weed is solanum dulcamara- called among many other things, bitter nightshade. It's a member of the solanum genus - which includes potato, tomato, and eggplant, all in the solanoideae subfamily (sister to the subfamily nicotianoideae!) of plant family solanaceae (the hierarchy of botany is so confusing!) - solanoideae subfamily also includes capsicum (chili peppers, paprika) - solanaceae family (the larger group, I think) does include belladonna - deadly nightshade.
As far as edible fruit/vegetables go, solanaceae is pretty damn useful- lookit-
* Chili pepper
* Eggplant
* Garden huckleberry
* Goji berry
* Ground cherry
* Potato
* Sweet pepper
* Tamarillo
* Tomatillo
* Tomato
...we can eat the fruit/tubers of these plants but the foliage is without exception poisonous, to some degree. Though I suppose chewing tobacco leaf is almost like eating it.

I cut and pasted the good parts from the Wikipedia site here - it makes sense that people would have been afraid to eat tomatoes, and that tobacco is such a popular drug - it seems like these alkaloids would have a suppressant, calming effect, as long as you can control the dosage and not send yourself into a coma.
"The Solanaceae family is characteristically ethnobotanical, that is, extensively utilized by humans. It is an important source of food, spice and medicine. However, Solanaceae species are often rich in alkaloids whose toxicity to humans and animals ranges from mildly irritating to fatal in small quantities."
"Solanaceae are known for possessing a diverse range of alkaloids. As far as humans are concerned, these alkaloids can be desirable, toxic, or both, though they presumably evolved because they reduce the tendency of animals to eat the plants.
One of the most important groups of these compounds is called the tropane alkaloids. The term "tropane" comes from a genus in which they are found, Atropa (the belladonna genus). The belladonna genus is so named after the Greek Fate, Atropos, who cut the thread of life. This nomenclature signifies the toxicity and lethality that has long been known to be characteristic of these compounds."
"...they are the most powerful known anticholinergics in existence, meaning they inhibit the neurological signals transmitted by the endogenous neurotransmitter, acetylcholine. Symptoms of overdose may include dry mouth, dilated pupils, ataxia, urinary retention, hallucinations, convulsions, coma, and death."
"A famous alkaloid from the Solanaceae family is nicotine."

What's the point of all this? I dunno. This is just the kind of stuff I like to learn about. You see a cluster of weeds at the side of the road - they may or may not be useful to you personally, but that doesn't mean they don't have their own stories or significance. Lots of plants in un-lawned lots around here actually have proven medicinal value - we just happen to live in a place and time where we're privileged enough that we don't have to make it for ourselves, and so don't need to learn to recognize the differences between, say, mullein and bindweed.

My reference and its reference: (Kate would kill me for bad form, but you know what - though I have no intention of ever plagiarizing anything, I hate how rigid the rules are for formatting this shite)


0. http://en.wikipedia.org/wiki/Solanaceae
1. "Solanaceae Juss., nom. cons.". Germplasm Resources Information Network. United States Department of Agriculture. 2007-04-12. http://www.ars-grin.gov/cgi-bin/npgs/html/family.pl?1043. Retrieved 2009-04-16.
2. Yasin J. Nasir. "Solanaceae". Flora of Pakistan. http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=10828.
3. Griffin WJ, Lin GD (March 2000). "Chemotaxonomy and geographical distribution of tropane alkaloids". Phytochemistry 53 (6): 623–37. doi:10.1016/S0031-9422(99)00475-6. PMID 10746874. http://linkinghub.elsevier.com/retrieve/pii/S0031-9422(99)00475-6.
4. "Solanine poisoning". Br Med J. 2 (6203): 1458–9. 1979-12-08. PMID 526812.
5. Alexander RF, Forbes GB, Hawkins ES (1948-09-11). "A Fatal Case of Solanine Poisoning". Br Med J. 2 (4575): 518. doi:10.1136/bmj.2.4575.518. PMID 18881287.