One of the most distinctive terrestrial adaptations in the Plantae is the retention of eggs by the parent diploid sporophyte, where they are fertilized and derive nutrition as a developing embryo. Green algae, while they may exhibit alternation of generations, lack embryos. A delay in zygotic meiosis could have produced the first multicellular diploid sporophyte. Celakovsky's Hypothesis , proposed 34 years before Bower in 1874, proposed that land plants arose from green algae already in possession of two alternate generations. As you might expect upon examination of the above phylogeny, there are a multitude of plant life cycles representing a wide variety of adaptations, ranging from subtle to obvious.
Most plants are capable of asexual reproduction .
This they accomplish by means of specialized organs called propagules . Asexual reproduction is alternatively known as vegetative reproduction . Aspens, dandelions and strawberries are examples. By avoiding meiosis, offspring are genetically identical clones of their parent. The oldest known living clone is a 12,000 year old creosote bush in the Mohave Desert.