is a small genus of Elaeagnaceae having a terminal taxon with seven species recognized, as of 2002. Hippophae rhamnoides is a highly variable species with eight subspecies. In ancient times, leaves and young branches from sea buckthorn were supposedly fed as a remedy to horses to support weight gain and appearance of the coat, leading to the name of the genus, Hippophae derived from hippo (horse), and phaos (shining). Distribution Hippophae rhamnoides, the common sea buckthorn, is the most widespread of the species in the genus, with the ranges of its eight subspecies extending from the Atlantic coasts of Europe across to northwestern Mongolia, northwestern China and Northern Pakistan. In western Europe, it is largely confined to sea coasts where salt spray off the sea prevents other larger plants from outcompeting it. In central Asia, it is more widespread in dry semi-desert sites where other plants cannot survive the dry conditions. In central Europe and Asia, it also occurs as a sub-alpine shrub above the tree line in mountains, and other sunny areas such as river banks where it has been used to stabilize erosion. They are tolerant of salt in the air and soil, but demand full sunlight for good growth and do not tolerate shady conditions near larger trees. They typically grow in dry, sandy areas. More than 90% or about of the world's natural sea buckthorn habitat is found in China, India, Pakistan, Mongolia, Russia, northern Europe, Ukraine, and Canada, where the plant is used for soil, water and wildlife conservation, anti-desertification purposes, and consumer products. Sea buckthorn USDA hardiness zones are about 3 through 7. Varieties During the Cold War, Russian and East German horticulturists developed new varieties with greater nutritional value, larger berries, different ripening months and branches that are easier to harvest. Over the past 20 years, experimental crops have been grown in the United States, one in Nevada and one in Arizona, and in several provinces of Canada. Genetics A study of nuclear ribosomal internal transcribed spacer sequence data showed that the genus can be divided into three clades: H. tibetana H. rhamnoides with the exception of H. rhamnoides ssp. gyantsensis (=H. gyantsensis) remaining species A study using chloroplast sequences and morphology, however, recovered only two clades: H. tibetana, H. gyantsensis, H. salicifolia, H. neurocarpa H. rhamnoides Natural history The fruit is an important winter food resource for some birds, notably fieldfares. Leaves