Spider are apparently absent. In some species, the exocuticle of the legs and prosoma is modified by a tanning process, resulting in brown coloration. Bilins are found, for example, in "Micrommata virescens", resulting in its green color. Guanine is responsible for the white markings of the European garden spider "Araneus diadematus". It is in many species accumulated in specialized cells called guanocytes. In genera such as "Tetragnatha", "Leucauge", "Argyrodes" or "Theridiosoma", guanine creates their silvery appearance. While guanine is originally an end-product of protein metabolism, its excretion can be blocked in spiders, leading to an increase in its storage. Structural colors
Garden centre Garden centre A garden centre is a retail operation that sells plants and related products for the domestic garden as its primary business. It is a development from the concept of the retail plant nursery but with a wider range of outdoor products and on-site facilities. It is now usual for garden centres to obtain their stock from plants which have been propagated elsewhere, such as by specialist nurseries or wholesalers. Garden centres are primarily found in Europe. A garden centre in the UK sells plants, compost, fertilizers, tools and landscaping products such as statues, furniture and garden ornaments. Some