Well, the observation that it acted like an annual - did not winter over from the root, in any case - means that it
could be an annual species, such as
Leptosiphon grandiflorus, which it resembles.
It doesn't conclusively mean that it MUST be an annual species or that it must be
Leptosiphon grandiflorus... but it does resemble that species, and the plant's behavior does not preclude that ID.
If it wintered over, then it would have to be a perennial or biennial species, which would exclude
Leptosiphon grandiflorus.
It's hard to find photos of
Leptosiphon grandiflorus that show the foliage - here's what I found:
https://c2.staticflickr.com/4/...
http://calphotos.berkeley.edu/...
If the foliage shown in Caroline's photo belongs to the flowering plant, then both the flowers and foliage appear to match these photos of
Leptosiphon grandiflorus.
Leptosiphon nuttallii appears to have needle-like foliage:
http://www.worldbotanical.com/...
However, some photos I found that were claimed to be
Leptosiphon grandiflorus also had needle-like foliage, so I don't know. Without finding a key and grinding through it, I don't know how these species are distinguished.
