Cupressus Conservation Project. This Conservation Project aims at planting groves of endangered species of Cupressus, namely Cupressus stephensonii, Cupressus atlantica and Cupressus dupreziana. Other vulnerable species will not be neglected.

conifers.org: The Gymnosperm Database: natural history, botany and taxonomic information on conifers, cycads, ginkgo and related plants.

Hawaiian Ecosystems at Risk project (HEAR): invasive species information for Hawaii and the Pacific. The goal of the Hawaiian Ecosystems at Risk (HEAR) project is to provide resources (technology, methods, and information) to resource managers statewide to aid in the fight against invasive alien species in Hawaii and the Pacific.

Plant Mail Order and Retail Nursery offering a detailed descriptive catalog of 4,500 plant cultivars yearly. Shipping nationwide and to many parts of the world.

Source for Hellebore, Hydrangeas, Primula and other rare plants, perennials, shrubs, trees and conifers.

Floridata is a free online plant encyclopedia featuring a photo reference of plants and special features on gardening, the environment and natural science.