Group of plants evolved from common ancestor.
The taxonomic sub-groups within cladistics.
An exclusive group of plants in which each member is more closely related to the others than any member is to a member of another group.
A term which originally referred to a group of descendants from a single biological organism, that is, having a common ancestor. It has been suggested that the concept could be used to depict graphically the situation with human immunodeficiency virus (HIV) infections. The usual illustration is that HIV infections are like an iceberg, with the visible portion consisting of the proportion of the persons who are clinically ill with acquired immunodeficiency syndrome (AIDS), in contrast with the sub¬ merged portion consisting of the number who are infected, but clinically well at any given time. The iceberg analogy is flawed because an iceberg melts and disappears, while the clade (and HIV infection) is a constantly growing number. The HIV clade could be graphed with numbers of cases along the vertical axis, and time along the horizontal axis. Those above a straight horizontal line beginning at the first description of HIV infections would be living cases of AIDS; those below it would be the infected but clinically well. The graph would look like the letter “V” on its side, with the point of the “V” to the left and the open side growing larger with time.
A group of related living organisms that share specific genetic material.