HIPPOPHAE RHAMNOIDES.--Sea Buckthorn, or Sallow Thorn. Though generally considered as a sea-side shrub, the Sea Buckthorn is by no means exclusively so, thriving well, and attaining to large dimensions, in many inland situations. The flowers are not at all conspicuous, but this is amply compensated for by the beautiful silvery-like leaves and wealth of fruit borne by the shrub. In not a few instances, for fully a foot in length, the branches are smothered with crowded clusters of bright orange berries, and which render the shrub during November and December both distinct and effective. It does best in sandy soil, and is readily increased from suckers, which are usually plentifully produced by old plants. For sea-side planting it is one of our most valuable shrubs, succeeding, as it does, well down even to high water mark, and where the foliage is lashed with the salt spray. HOLBOELLIA. HOLBOELLIA LATIFOLIA (_syn Stauntonia latifolia_).--Himalayas, 1840. An evergreen climbing shrub that is more often found under glass than out of doors. In the South of England, however, it is quite hardy against a sunny wall. It grows 12 feet high, with shining green leathery leaves, and fragrant purplish-green flowers. H. latifolia angustifolia has decidedly narrower leaves than the species, but is in no other way different. HYDRANGEA. HYDRANGEA ARBORESCENS.--North America, 1736. This is a plant of large growth, but the flowers are greenish-white, and by no means conspicuous. H. HORTENSIS (_syn Hortensia opuloides_).--China, 1790. This is an old-fashioned garden shrub that is only hardy in the south and west of these islands and in the vicinity of the sea. In some of the forms nearly all the flowers are sterile, the calyx-lobes being greatly expanded, and in others the outer flowers only are sterile. According to the nature of the soil the flowers vary much in colour, some being pure white, others pink, and others of varying shades of blue. There are some very beautiful and distinct varieties, such as H. hortensis japonica; H. hortensis Otaksa, with large panicles of sterile blue flowers; H. hortensis rosea-alba, with large rosy flowers; H. hortensis Thomas Hogg, a very free-flowering and welcome form; H. hortensis mandschurica, and H. hortensis stellata flore-pleno, with partially double flowers, are worthy of attention. H. PANICULATA.--Japan, 1874. This is one of the most distinct species, in which the flower-heads are elongated, not flat, as in most other species, and from which the finest form in cultivation has been obtained. This is H. paniculata grandiflora, in which the flowers are sterile and pure white, forming large panicles often a foot in length. It is a magnificent variety, and, being perfectly hardy, should be extensively planted for ornament. The flowers are produced in late summer, but remain in good form for fully two months, dying off a rich reddish hue.