Семейство Кипарисовые: Распространение, характеристики и аллергенность.

Cypress family of conifers

Cupressaceae is a conifer family, the cypress, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioecious or (rarely) dioecious trees and shrubs up to tall. The bark of mature trees is commonly orange to red brown and of stringy texture, often flaking or peeling in vertical strips, but smooth, scaly or hard and square cracked in some species.

The leaves are arranged either spirally, in decussate pairs (opposite pairs, each pair at 90° to the previous pair) or in decussate whorls of three or four, depending on the genus. On young plants, the leaves are needle like, becoming small and scale like on mature plants of many genera; some genera and species retain needle like leaves throughout their lives. to 55°S in southernmost Chile (Pilgerodendron uviferum), further south than any other conifer species. Juniperus indica reaches 4930 m altitude in Tibet. Most habitats on land are occupied, with the exceptions of polar tundra and tropical lowland rainforest (though several species are important components of temperate rainforests and tropical highland cloud forests); they are also rare in deserts, with only a few species able to tolerate severe drought, notably Cupressus dupreziana in the central Sahara. Despite the wide overall distribution, many genera and species show very restricted relictual distributions, and many are endangered species. The world's largest (Sequoiadendron giganteum) and tallest (Sequoia sempervirens) trees belong to the Cupressaceae, as do six of the ten longest lived tree species.

The Cupressaceae trees contain a wide range of extractives, especially terpenes and terpenoids, both of which have strong and often pleasant odors. The heartwood, bark and leaves are the tree parts richest in terpenes. Some of these compounds are widely distributed in other trees as well, and some are typical for Cupressaceae family. The most known terpenoids found in conifers are sesquiterpenoids, diterpenes and tropolones. Diterpenes are commonly found in different types of conifers and are not typical for this family. Some sesquiterpenoids (e. g. bisabolanes, cubenanes, guaianes, ylanganes, himachalanes, longifolanes, longibornanes, longipinanes, cedranes, thujopsanes) also present in Pinaceae, Podocarpaceae and Taxodiaceae.

The pollen of many genera of Cupressaceae is allergenic, causing major hay fever problems in areas where they are abundant, most notably by Cryptomeria japonica (sugi) pollen in Japan. Highly allergenic species of cypress with an OPALS allergy scale rating of 8 out of 10 or higher include: Taxodium, Cupressus, Callitris, Chamaecyparis, and the males and monoicous variants of Austrocedrus and Widdringtonia. However, the females of some species have a very low potential for causing allergies (an OPALS allergy scale rating of 2 or lower) including Austrocedrus females and Widdringtonia females.