Annual Tasselweed

Annual Tasselweed has increased the specialization of its body and developed more specialized structures. The rhizome has developed into a more specialized holdfasting structure which anchors the Tasselweed to any solid part of the substrate such as rocks. They have developed a float structure filled with gases which provide lift and raise the Tasselweed high in the water. The connection from holdfasts to float is called a stipe and is flexible and durable, undertaking the major upward growth of the Tasselweed. The fronds now sprout just from the large float with many sets of them flowing in the currents.

The Annual Tasselweed no longer reproduces through fragmentation; it has developed to utilize metagenesis for reproduction. On its fronds, sporangia are made and release zoospores to develop into microscopic male and female gametophytes. The gametophytes will release gametes which fuse and, if they settle in favorable locations, will germinate into mature Annual Tasselweed sporophytes. The Tasselweed is an annual organism: in winter it is dormant as microscopic gametophytes and soon-to-grow sporophytes. In spring, the gametophyte stage has all died having produced as many sporophytes as possible, which then start to grow. They reach full size in summer and during fall they will begin to produce sporangia on their fronds which will form, make, and release zoospores and start the cycle again. Throughout their range they are most common on rocky coastlines and in inter-tidal zones. They provide temporary homes for many species.