Chamaecyparis lawsoniana is a cypress in the genus Chamaecyparis, family Cupressaceae, known by the name Lawson Cypress in the horticultural trade, or Port Orford-cedar in its native range (although not a true cedar). C. lawsoniana is native to the southwest of Oregon and the far northwest of California in the United States, occurring from sea level up to 1,500 m (4,900 ft) altitude in the Klamath Mountains valleys, often along streams.
It is a large evergreen coniferous tree, maturing up to 200 feet tall or more, with trunks 4–6 feet in diameter, with feathery foliage in flat sprays, usually somewhat glaucous blue-green in color. The leaves are scale-like, 3–5 mm long, with narrow white markings on the underside, and produced on somewhat flattened shoots. The seed cones are globose, 7–14 mm diameter, with 6-10 scales, green at first, maturing brown in early fall, 6–8 months after pollination. The male cones are 3–4 mm long, dark red, turning brown after pollen release in early spring. The bark is reddish-brown, and fibrous to scaly in vertical strips.
It was first discovered (by Euro-Americans) near Port Orford in Oregon and introduced into cultivation in 1854, by collectors working for the Lawson & Son nursery in Edinburgh, Scotland, after whom it was named as Lawson Cypress by the describing botanist Andrew Murray. The USDA officially calls it by the name Port Orford Cedar, as do most people in its native area, but as it is not a cedar, many botanists prefer to avoid the name, using Lawson Cypress, or in very rare instances Port Orford Cypress, instead to stop confusion. The horticultural industry, in which the species is very important, mostly uses the name Lawson Cypress. There is some confusion amongst non-professionals who use the variant Lawson's cypress. Although considered incorrect, this name is widely used.
The extinct Eocene species Chamaecyparis eureka, known from fossils found on Axel Heiberg Island in Canada, is noted to be very similar to Chamaecyparis pisifera and C. lawsoniana.
Read more about Chamaecyparis Lawsoniana: Cultivation and Uses, Disease