entry dated April 24, 2023, issued from near Tequisquiapan, elevation about 1,900m (6200 ft), Querétaro state, MÉXICO (~N20.55°, ~W99.89°)
BLACK NIGHTSHADE

The above plant is green and flowering now only because it grows beside the trunk of a tree in a small village's backyard, where someone waters the tree. Elsewhere in the landscape, here at the end of a prolonged and unusually severe dry season, things are parched and mostly brown and gray. Even at a distance, the small white, star-shaped flowers clustered on a dark green herb with simple leaves told me that this was a species of black nightshade, genus Solanum, of the Black Nightshade/Tomato/Potato family, the Solanaceae. Solanum is a huge genus, complex, and not well understood. To name them, you must "do the botany."

The flowers with their five stamens side-by-side, gradually diminishing toward their tops and forming a kind of "nose" on the blossom, is classic nightshade. It happens that anther link is a vital field mark for determining which species you have, so here's that:

The anthers are about 2mm long (0.08 inch), which disqualifies the very similar and abundant Solanum americanum, for that species' anthers hardly exceed 1.5mm in length.

Leaf undersides also generally are less hairy than Solanum americanum. Note that the sparse hairs lie close to the leaf surface and curve away from the stem, plus some of the hairs enlarge at their bases into glands.

As seen above, our plant's fruits, very much like little green tomatoes, are still immature.

All the above features, especially the anther length and the particular nature of the hairs, lead us to SOLANUM NIGRESCENS, which shares its name of Black Nightshade with some other species, particularly Solanum americanum and Solanum nigrum. Our Solanum nigrescens is common to abundant from the southern US south through most of South America and the Caribbean, plus here and there worldwide as an invasive weed.

There's been such confusion about what Solanum nigrescens really is, especially with regard to Solanum americanum and Solanum nigrum, that one wonders if now the issues are settled. I'm trying to base our identification on descriptions in the 2019 work by Sandra Knapp and others entitled "A revision of the Morelloid Clade of Solanum L. (Solanaceae) in North and Central America and the Caribbean."

entry dated May 26, 2023, issued from near Tequisquiapan, elevation about 1,900m (6200 ft), Querétaro state, MÉXICO (~N20.55°, ~W99.89°)
BLACK NIGHTSHADE' BLACK FRUIT

The above berry-type fruits developed from the same plant profiled atop this page. The ruler marks are in millimeters.

from the April 28, 2007 Newsletter issued from Yerba Buena Clinic just outside Pueblo Nuevo Solistahuacan, Chiapas, MÉXICO
about 1740 meters in elevation, ± LAT. 17° 11' 27"N, LONG. -92° 53' 35"W
EATING BLACK NIGHTSHADE
At some point many years ago a certain book taught me to call a certain species "Deadly Black Nightshade." Because of that name, during most of my life I've regarded it as poisonous and when I picked Lambs-quarters, for example, as a potherb, I'd make sure that none of it got into my pot by mistake. You can see some of the plant,Solanum nigrescens, growing next to my casita below:

When I learned that Potato and Eggplant also are members of the genus Solanum, and that nowadays even Tomato plants are placed in the genus, I began wondering about S. nigrum's poisonous qualities. Of course it's true that green potato tubers are poisonous and that tomatoes used to be regarded as deadly, too, so the genus Solanum's aura of being possibly dangerous was never completely dispelled. Bailey's Manual of Cultivated Plants says that unripe fruits and leaves may be poisonous, but all my Mexican books agree that tender young shoots are edible.

In fact, people here, who call the plant Hierba Mora, regularly its tender shoots as a potherb, and I've begun throwing a few shoot-tips into my morning stews, too. There's not much taste to them, except a little bitterness, but when you're feeling the need for green, leafy vegetables, they're fine.

Solanum is one of the largest of all plant genera, holding about 1700 species, so it's good to be able to identify the genus in the field. Here's how to recognize the genus Solanum: