Next time you're browsing at the local garden center, consider Dolly. During the recent brouhaha over this chubby little lamb, the first mammal ever cloned from a single adult cell, not one politician or pundit noted that in horticulture cloning has been a routine procedure for decades. That's the only way to preserve choice characteristics of the parent plants, whether a lanky growth habit, giant flowers, or an unusual leaf color. One reason the cloning of mammals came later than that of plants is because there are more biological roadblocks to the former. Chop off a human thumb, for example, and you're left with nothing but a stump.
Leaves can regenerate both roots and shoots.
Nevertheless, the implications of plant cloning, though less obvious than those of cloning mammals, especially humans, are still worth pondering. At first glance, asexual propagation would seem to be, as critics claim, an unmitigated disaster for genetic diversity, the most basic level of the diversity of life. But it's not quite so simple. Perhaps we humans are prone to such oversimplifications because we're large animals, and large animals tend to be rather drab in the bedroom department. We must pair up to reproduce.