Introduction to useful plants
A useful plant is simply a plant used by man (strictly speaking, no plant is useless). It can be used:
- whether it is a wild plant, a weed or a crop;
- with very diverse purposes: human or animal food, technical uses, auxiliary plants for agriculture or environment, medecine, pleasure or culture;
- at different periods: from prehistory to contemporary times;
- at very different scales: from a village to the globe;
- with diverse social statuses: from famine food to highly valued specialties.
How many useful plants in the world?
As a gross estimate, there are 7-8,000 crops (cultivated species), and the total number of useful species may be more than 34,000. In fact, it is quite impossible to give a precise and exhaustive list of useful plants, because:
- explicit or implicit criteria vary from one source to the other;
- inventories are based on names, and recent taxonomic revisions are often lacking to identify synonyms;
- there is no consensus between specialists on classification, above all of crops. For example, the Citrus genus includes 16 species according to Swingle and 162 according to Tanaka.
- even if we reach a consensus at the level of biological species, we have to decide whether inventories deal with species or crops. For example, rape (canola) and swede belong to the same species (Brassica napus). Chicory (witloof) and radicchio (Cichorium intybus) as well, or jute and meloukhia (Corchorus olitorius). For producers and users, they are different crops.
Global inventories before Internet
- Kunkel (1984) : 12 650 'food plants'
- Uphof (1968) : more than 6 000 'economic plants'
- Mansfeld (2nd edition, Schultze-Motel, 1986): 4 800 'crops' (excluding forest trees and ornamentals)
- Mansfeld (3rd edition, Hanelt and IPK, 2001): 6 100 'crops' (excluding forest trees and ornamentals)
Other books offer lists of variable interest (Facciola, 1990; Sánchez-Monge, 1991; Tanaka, 1976).
Global inventories on Internet
This is the most complete base, constituting the 'taxonomic core' of the information system of the United States on genetic resources, and including 26 462 genera and 89 533 species. Given its purpose, all the relative species susceptible to be used as genetic resources are included, as well as ornamentals and timbers. Moreover, species considered as noxious weeds, rare and threatened species, and species included in the annexes of the CITES Convention are also included.
Electronic version of the 2001 book.
It is not exactly an inventory, but this site contains resources on a great many plant species. Created by Wayne P. Armstrong (San Marcos, Califormia), it gives many fascinating and scientifically accurate data about useful plants, with many good photographs. The link given is a portal arranged according to the alphabetical order of botanical families, with internal links to all particular pages.
Inventories by use group
They are listed in the page of the use group concerned (e.g., vegetables, timbers...)