Asparagus (genus)
Asparagus is a genus of flowering plants in the family Asparagaceae, subfamily Asparagoideae. It comprises up to 300 species. Most are evergreen long-lived perennial plants growing from the understory as lianas, bushes or climbing plants. The best-known species is the edible "Asparagus officinalis", commonly referred to as just "asparagus". Some other members of the genus, such as "Asparagus densiflorus", are grown as ornamental plants. Ecology. The genus includes a variety of living forms, occurring from rainforest to semi-desert habitats; many are climbing plants. Most are dispersed by birds. Ornamental species such as "Asparagus plumosus", "Asparagus  aethiopicus", "Asparagus setaceus", and "Asparagus virgatus" are finely branched and are misleadingly known as "asparagus fern". In the Macaronesian Islands, several species (such as "Asparagus umbellatus" and "Asparagus scoparius") grow in moist laurel forest habitat, and preserve the original form of a leafy vine. In the drier Mediterranean climate the asparagus genus evolved in the Tertiary into thorny, drought-adapted species. Root tubers are storage organs developed by Asparagus spp. and are a valuable source of moisture and nutrition for species growing under drought conditions. Many species, particularly from Africa, were once included in separate genera such as Protasparagus and  Myrsiphyllum. However, partly in response to the implications of the discovery of new species, those genera have been reunited under "Asparagus". Species in this genus vary in their appearance, from unarmed herbs to wiry, woody climbers with formidable hooked spines that earn them vernacular names such as "cat thorn" and "wag 'n bietjie" (literally "wait a bit"). Most species have photosynthetic flattened stems, called phylloclades, instead of true leaves. "Asparagus officinalis", "Asparagus schoberioides", and "Asparagus cochinchinensis" are dioecious species, with male and female flowers on separate plants. Selected species. , the World Checklist of Selected Plant Families accepts 212 species of  Asparagus, including: Invasive species. "A. asparagoides", known as bridal creeper, is a problematic weed in southern Australia. "Asparagus asparagoides", "A. aethiopicus" (under the name "A. densiflorus") and "A. scandens" are listed on the New Zealand National Pest Plant Accord since they are invasive plants. "A. setaceous" is officially recognized as an invasive species in Rio Grande do Sul State, Brazil.