Solanum species in the San Francisco Bay Area

Nature Talk
1

I’ve been seeing a lot of IDs for Solanum douglasii on iNat. My question is, is this species more widespread than I had believed? The Jepson Herbarium certainly only has a few specimen records, Calflora has very few records, and the Marin Flora (2007) attributes S. douglasii as misidentified S. furcatum. With how similar white-flowered Solanum species are, particularly S. douglasii and S. furcatum, is it possible that iNat is full of misidentified Solanum?

1 Like
2

I would guess that it is not just possible but probable. I just took a quick look at S. douglasii observations, and almost every ID was based on Computer Vision. I suspect that many of the observers had no idea what species they were looking at.

4 Likes
3

iNat is full of misidentified anything, so you may want to add the species to cleaning AI topic.

2 Likes
4

Welcome to the forum, @nalden!

5

Thanks for the info. It helps as I’m still new to iNat. Where is the cleaning AI topic?

6

It’s mostly likely mixed, yes. Even down south these species are confused. Furthermore, americanum and nigrum are both troublesome to distinguish, so it isn’t just furcatum and douglasii that are an issue.

7

I failed to find Solanum furcatum when I visited the Bay Area, and this was one of the plants I wanted to resolve the ID of. However, looking at iNaturalist, I see a large number of plants under Solanum douglasii that do not look like douglasii, or americanum, but something “else”. I have a suspicion that these plants then represent furcatum. The most obvious character if I’m correct is that the anthers are very short, resembling americanum, but the flower itself is large. The petals seem to spread out more than they do in douglasii, both can be purplish-tinged or white. The green “star” at the center of the flower is usually dark or lined with dark marks in douglasii, whereas these furcatum appear to remain plain green here. Berries are shinier in douglasii and turn black, while furcatum berries are not so shiny and seem to stay greenish or sometimes nearly purplish.

I’ll see what else I can find regarding the ID of these two, as the main feature, the branching of inflorescence, is hard to see in photos.

1 Like
8

These images are from the Bay Area, and were used to illustrate S. furcatum in a revision of the Old World Solanum nigrum group:
https://phytokeys.pensoft.net/article/21991/zoom/fig/114/

This image confirms that the fruit are quite dull and not mildly shiny, which tends to be the case in douglasii. It shows the branching in the inflorescence quite clearly, but again an annoying feature to use on the average iNat observation. The anthers are a bit longer than the suspicious douglasii records on iNat, which is perplexing. I’m also seeing that specimens of douglasii, which are certainly douglasii, from further north have mildly different flowers to those I see down south, which explains some of the difference. Hmm. Well, this probably helps explain why these two are almost certainly mixed up on iNat.

9

I just think it’s really neat to think of Solanum in Solano County.

10

Thanks for all the detailed info. I’ll keep two eyes open for S. furcatum

11

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.