Is the referenced book "Trees of San Diego: A Pictorial Guide" by Patricia Waldron? Or is it "Common Plants and Trees of San Diego" by Wilson Harlan? Or is it something else? Thanks.

I think you might be overestimating the warming effects of the ocean there. When the cold events hapen, the prevailing air flow is over the land from the N.W. and thus, you are unlikely to see any impact. Also, I live in North Florida, away from the coast in z 8b and have driven the exact area you mention during the past two winters. Both times I was struck by cold damage I observed to Washingtonia robusta, Syagrus(queen palm) and oleander that were unaffected at the same time here in Gainesville. Thus, I think zone 8a is more likely. Plus, look at the average lowest temps. at Jekyll Island, GA for comparison - even there zone 8 temps are recorded frequently. That said, I think you have a great idea and opportunity. The species that Resin have suggested sound good to me too, but I would also add Araucaria angustifolia. This species looks to be very promising for this area of the country. It loves heat and humidity (unlike araucana), yet seems very hardy. There is a 40'+ tree that is only 12 years old!! at the Atlanta Botanical Garden. It is in superb shape and obviously fast grower (compared to araucana). There are others here in Florida as well and they are very similar to araucana in youth and very primitive looking. A. bidwillii is worth a shot - we have a few here in north Florida, but have been known to die after exceptionally cold winters. Resin is right - no Agathis north of Orlando that I know of (I am trying A. atropurpurea, A. corbassonii, A. lanceolata, A. moorei, A. robusta, and A. vitiensis here)...Others to try include Dacrydium cupressinum (doing well in a number of collections in the SE), Dacrycarpus dacrydioides (I know Podocarpaceae - but still cool), Callitris rhomboidea (doing well near Atlanta)...

"What an interesting developments so are the leaves just vestigial leftovers with little purpose?" Yep! Not sure they're even photosynthetic. "So I guess the proto-Conifer would have had needle leaves for sure?" Reasonable to assume, yes. All the various conifers with scale-leaves (cypresses, etc., etc.) all start off with needles in their juvenile phase, no conifer with needles starts off with scale leaves. So scale leaves are the derived feature, and needles the basal. It can however work the other way, e.g. Juniperus communis has gone back to needles, losing the scale leaves that its more immediate ancestors had. "Are all the phyllocladus confined to southern Britain" More western, than southern. They'll grow OK in e.g. western Scotland, and better there than in the southeast. "Same with sciadopitys, right?" Maybe; the precise derivation of its foliage is AFAIK still uncertain. "What other conifers are like this?" None. Unless one can argue a case for freak mutations like Cryptomeria japonica 'Cristata'. Resin

Wow, that's a lot of plants! I don't have a list of what I'm growing in my little gardens -- sometimes it takes me a couple of weeks in the spring to realize that that weird looking weed in the corner is something I've had for years. I just assume that more plants than not will grow in this area! One of the more unusual plants I grow is agapanthus. Not a particularly hardy variety, this was simply a florists' plant my mother gave me four years ago. But it's come up reliably every year for the past three seasons in Central Ohio. It's planted against a south-facing brick wall with excellent drainage, and apparently doesn't realize it's not in zone 8+ anymore! One of my mother's more spectacular plants is a 15 year old calamondin orange that arrived as a little "get-well" houseplant. It spends the winter on the unheated glassed in back porch in Cincinnati, and now stands over 6' tall in the pot, and is nearly 4' around. It always has flowers and fruit on it, and we've picked 200 ripe fruits at one time.