Californian Grusonia

[BarryRice]

Hey folks,

I found this Grusonia growing in the sandy, silty soil between the E-bound and W-bound lanes of I-10, Riverside County, west of Blythe. The Jepson Manual says it's either G. parishii or G. pulchella, but it wasn't in flower and I didn't look for characters that would help at this point.

Any ideas?

[vlani]

Must be parishii. Pulchella is very different and does not really occur in CA. Or if id does - it grows North of Death Valley, not in Riverside.

Looks different from parishii I've seen in Organ Pipe Park. Spines are thin.

[BarryRice]

Thanks!

G. pulchella is recorded further north in California (east of the Sierra, as in Mono and Inyo Counties, although I haven't checked which if not both counties supposedly have it), but I don't like to make IDs based purely on range.

[vlani]

Yes pulchella is recorded in CA but extremely hard to find. I have been to two of recorded locations in White Mountains with no success.

[peterb]

Making IDs based on range in the southwest US is a really good way to make IDs. Sometimes knowing a locale is just about all you need to know.

The pics you took look like Grusonia kunzei to me, the Colorado Desert's common dog cholla.

peterb

[CoronaCactus]

Definetely G. kunzei. Especially along I-10. Near the stateline of CA and AZ they can be found all over, don't even need to stop, you can see them right at the edge of the interstate. But of course, it's no fun just seeing them at 70mph

[BarryRice]

Darryl,

You really think this is G. kunzei? That's not a species listed for California in the Californian floristic works, Flora of North America, or other works...

B

[peterb]

aha, interesting. G. kunzei is fairly common up along 95 from Quartzsite all along the western edge of AZ. But in double checking Benson and others, it does appear that the form found in California is more likely to be parishii. Of kunzei in CA, Benson writes: Although the variety does occur just east of the Colorado River in Yuma County, Arizona, no specimens from across the river in California have been seen." However, distribution of parishii is given as follows: Death Valley region, Inyo County, E San Bernardino and N. Riverside Counties from Joshua Tree National Monument NE across the mountain ranges of E Mojave Desert." So, I guess you found parishii. Nice plants! I am only familiar with parishii from the Casa Grande AZ region (what Benson called "peeblesianus" but that name is no longer accepted) and in huge mats down southeast of Why, AZ.

peterb

[BarryRice]

I don't know, offhand if Peebles predates or post-dates the building of I-10. One might expect that the high velocity winds of I-10, from traffic, might carry propagules along its length?

[vlani]

How large are the segments? G. kunzei is a much large variant, otherwise very similar plant to parishi.

It is very possible that the plants were somehow brought along I-10 with the passing car or track, and found that spot suitable. Not with just winds of cause.