I have been breaking my head trying to identify this plant for a couple of months. It's a volunteer in my Southern California native garden. I have never seen a plant like this, whether in any of the numerous botanical gardens, native plant nurseries, "regular" nurseries, or hiking. There are no plants like this anywhere in the neighborhood that I've seen either. The plant is probably about 6 - 9 months old and about 9 inches tall. The leaves are alternate and they are covered in wooly, almost cotton-like hairs. It reminds me of an extra-fuzzy Asclepias eriocarpa. The leaves are very narrow and curve downward along the midrib. The color is strikingly white - even more so than the photographs suggest. It looks similar to some of the Salvias, but it doesn't have any detectable odor when the leaves are bruised/crushed. Any help is appreciated.
Sorry for the delay in responding. I believe that is correct. Thank you. According to CalFlora it's a common plant, but I've never seen it before. I look forward to watching to develop. It really is a striking plant. I'm surprised native nurseries don't sell it on a regular basis since they sell other Pseudognaphallium species.
My experience is that with supplemental watering it grows into a bushy, spherical, brilliant white plant and has a faint but pleasant scent, especially in damp weather; but when it begins to send up flowering stalks it becomes an unattractive mess. If I weren't so deep in the city and thus out of the flight path of painted ladies, I might stop pulling the seedlings out and leave them to feed caterpillars.
I live right at the foothills of the SF Valley, so I get all kinds of volunteer seedlings in my yard. I've got Malosma laurina seedlings coming out of my ears - some Ribes, Artemisia californica, Encelia californica, and even some Rhus integrifolia volunteers too. I usually dig them up and pot them for gifting to others with native landscapes. I prefer a wild plant to nursery stock any day. I don't mind the "wild" look too much, although I find I don't like how ratty the sages and Encelia get over the summer. Lots of wildlife though.