Its Oxalis stricta, a common weed.
I did like your Dudleya photos. You need to head for the coast and further
south to find more interesting species than the common Dudleya cymosa.
BTW, your mystery Euphorbia is probably E.pugniformis.
"Brian" <ard at mad.scientist.com> wrote in message
news:8sahvq$629$1 at slb7.atl.mindspring.net...
> Greetings all,
> I live in San Francisco. Thus much of what grows around here is not
> and I have had zero luck trying to find a name for this one.
> A few points that may help...
> I took a cutting of this plant in early June (when the dry season starts
> here) when the flowers had faded. Actually, I have been watching this
> for years, being the only one of its kind I have located. It grows on a
> sunny hillside next to a path I use when hiking. On that day in June I
> noticed a branch close to the path had been recently broken off and
> to take advantage of the situation. The main stem is woody, the leaf
> seem "succulent", the leaves three lobed. A "cool" thing about this plant
> is the behavior of the leaves, during the day they are as seen in the
> photos, but at night they fold upwards as if to protect itself somehow.
> (What would the term for this action be?) It won't start raining
> here until about Nov. so the parent plant looks rather ratty at this point
> (few and small leaves at the stem tips).
> That is about it. The URL is www.dreamwater.com/dudleya/q4.jpg
> Any help on the approximate binomial is greatly appreciated.
> Thanks in advance,