Dear Sam,
A fine book on Lewisia is a book by that name by the late Roy
Davidson. The book is available on line and, I am sure, through the North
American Rock Gardening Society.
Seed sources are of two kinds: seed exchanges and wild seed
collectors. The advantage of seed exchanges is that usually a large number
of species are available if you are a member and they are free. Seed
exchange seeds are great when beginning with a new genus. You can develop
the growing methodology without making a large outlay. The down side is
the seed may be mis-labled, may be cross breds, may not be viable.
Alternatively, correctly identified but a smaller number of
species can be gotten from wild seed collectors like:
Northwest Native Seed (Ron Ratko)
oreonana@juno.com
There is a small ($3?)fee for the first catalog. In his 2003 Catalog, Ron
offered 19 different genera/species He accepts credit cards
Southwestern Native Seed.
Box 50503 Tucson,AZ 85703
Nominal charge ($2)for first catalog SNS offered fewer than 1/2 dozen
genera/species. No credit cards, no phone, no fax. Just mail.
For the serious hobbyist, their catalogs are worthwhile because of the
number of other genera offered.
Out PBS members will inundate you with their favorites. My
favorite general bulb books are John Bryan's 2 volume 'Bulbs' sadly out of
print; his revised 'Bulbs' and 'The Manual of Bulbs' from the Royal
Horticultural Society. For going "deep" it is well to buy the one genus
books.
Best of luck.
mailto:onager@midtown.net