When a group of related plants is described or revised, a key is usually given to separate them and narrow down the possibilities, group by group, character by character. Different formats of key are used, and how straightforward or cumbersome they are is often a good test of whether the plants are clearly separated entities and how well they are actually known and described. As different plants can evolve similar characteristics independently, the larger a geographical area is encompassed within a key to its plants, the more complicated the keys become, and the harder it is to identify plants.
Unfortunately bamboos are inherently variable and often very closely related, and they sometimes cannot be clearly separated using single-character keys. There is so much variation within each species that it is often difficult to construct a simple key that always works well, and many entries in a bamboo description are generalisations to a certain extent. When keys are written from descriptions rather than from real plants or specimens, they become far from infallible.
Keys can sometimes only be taken as a helpful guide to the kinds of characters that are important for the separation of a group of species. They should give an indication of which group of related species a plant belongs in, and allow a shortlist of possible candidates to be drawn up. The individual descriptions then have to be consulted to find the description that matches most closely. ... More
Querying an online database of characters will be a better solution to the identification problem in the future. Before that is feasible, however, the taxonomy and descriptions will have to be drastically improved, and many character states need to be reassessed to make them more comparable, and more consistently applied. To make a start, morphological characters of bamboos were revised so that bamboos could be incorporated into the database of grass species at Kew, and the character list is available. The DELTA dataset can be used to make keys using INTKEY software. However, the coding of the bamboos included in the database has mainly been undertaken from the original descriptions or inadequate revisions, and most descriptions still vary too widely for accurate comparison.
Keys to the genera of cultivated bamboos have been produced in connection with the Flora of North America project. These, like most keys, assume a degree of knowledge of the morphology of bamboos. To help in their interpretation they will be presented here with linked illustrations.
Hopefully at some point there will be enough reliable information on the characteristics of bamboo species, along with consistently understood and applied terminology. This will allow the production of interactive online keys using software such as Lucid. For examples of such keys see the online Araceae keys of the CATE-Araceae project.