Glossary of plant morphology others may form a tight spiral, or whorl, around the flower stem. First, at the base, are those non-reproductive structures involved in protecting the flower when it is still a bud, the sepals, then are those parts that play a role in attracting pollinators and are typically coloured, the petals, which together with the sepals make up the perianth (perigon, perigonium). If the perianth is differentiated, the outer whorl of sepals forms the calyx, and the inner whorl of petals, the corolla. If the perianth is not differentiated into sepals and petals, they are collectively known as tepals. In some
Surround sessions experience. This new method of packaging ads does not require longer download times, more screen space, or annoying browser tricks. Surround sessions Advertising sequence in which a visitor receives ads from one advertiser throughout an entire site visit. Recently introduced by the online unit of the New York Times, the "surround session" is creating a major buzz in the online advertising community. The session model represents a potentially significant shift in the way advertisers view online media, as more emphasis is placed on the real interaction between advertisers and audiences. In a surround session, an advertiser has all or most