To the user who would like to determine the genus of an unknown orchid this website offers three independent ways. The first, and simplest, would be to open the Higher Taxa module and to scan al descriptions and all images until a matching description or picture is found. But this is quite a tedious process (there are 132 genera and several hundreds of images in the Higher Taxa module), and especially when the user exclusively relies on images it may lead to misidentifications. Orchids from different genera can resemble each other closely, as for example Agrostophyllum (OR20-120.JPG) and Glomera (OR16-119.JPG). There are many cases where it would be easy to jump the wrong conclusion a better way is use either Single-access keyor the Multi-entry key. The first is a traditional dichotomous key, where a series of choices between two alternatives guides the user to the correct genus (if all goes well). This key has the advantage that the choice as to which characters to consider has already been made. It also has the advantage that it always terminates with a unique result. It may ask the user, however, to examine characters that are difficult to observe, or that are absent on the specimen at hand (which is perhaps only a detached flower).
The last disadvantage is overcome by the Multi-entry key. This module looks more complicated than the Single-access key, but it is in fact easier to use. The idea is for the user to examine his unknown plant very well and then to choose a number of character states that have been observed. For example, if the flower has a spurred lip and the plant has pseudobulbs then this combination of two easily observed character states can be entered. In the list of genera on the right of the screen the match percentage will be shown. Those that score 100% possess both characters, while those that score 50% possess only one of the two - either a spurred lip, or pseudobulbs, but not both. Others will score 0%, those genera have neither pseudobulbs nor a spurred lip. Please note that a 100% score for genus X does not guarantee that even a single species in that genus possesses both character states. It merely indicates that both character states occur in the genus, but possibly in different species (we may call this the spurious hit problem, which plagues keys of this type, and even more so the makers of such keys). Also note that unlike the Single-access key not all genera can be identified uniquely with the characters offered in the Multi-entry module. The user will in many cases end up with a short list of genera, where no additional choice of a character state will reduce this list. To proceed with the identification process it is then necessary to go to the Higher Taxa module and check the genera of the final list by reading descriptions and looking at pictures. Fortunately, it is quite easy to switch back and forth between the Multi-entry module and the Higher Taxa module (using the Go-button in the former and the Back-button in the latter).
The reason why Multi-entry works in this somewhat restricted way is that we would have to use quite complex combinations of characters rather than a set of relatively simple ones in order to be able to separate each and every orchid genus by some unique combination of character states and to avoid the spurious hit problem mentioned above. This can be done, but it would make using IdentifyIt so complicated that it would defeat its purpose.
Here is a more detailed description of the way Multi-entry is to be used:
Open Multi-entry by clicking on its icon in the Navigator or by selecting it from the Window menu. The field on the left contains the search pattern (the character states that you have chosen so far) while the field on the right lists all genera, along with the 'hit' percentage for each: the match percentage based on the search pattern.
To add one or more character states to the search pattern, click on the Add... button below the search pattern field. The Edit Search Pattern window will now open. Click on a character in the top list, then click on one or several character states in the list below.
You can change the sort order of the genera, characters, and states by clicking on the Sort ... button or by choosing Change Sort Order ... from the Multi-entry menu. This opens the Sort Order dialog box, where you can choose the sort order for each from the popup menus, and set the sort direction to ascending (low to high) or descending (high to low) for each. The sort order for genera should be set to descending match percentage, so that the genus with the closest match (highest percentage) is listed first. To identify your specimen in the smallest possible number of steps, you should also set the sort order for characters to descending separation coefficients. This will rearrange the characters so that the next best character to add to the search pattern will be on top of the list. The separation coefficient values, shown to the left of the character names, are recalculated every time you change the search pattern. Sometimes one of the possible character states will be named 'not applicable'. This may be chosen, for example, when you are asked to examine the indumentum of the leaf sheath of a plant that does not have a leaf sheath.
When you click on OK, the selected character states are added to the search pattern and the match percentages are automatically updated. You can jump to the page in the HigherTaxa module for one of the genera by clicking on its name in the list of genera and then clicking on Go. From the Higher Taxa module you can return to the Multi-entry module by clicking on Back.
Keep in mind that the Multi-entry search results always give the percentage match between the states you have selected for searching and the states that are linked to the objects. Thus, if you have selected many states for a search pattern, it is possible that no genus will have a 100% match. This is an advantage, however, as it may prevent you from missing a correct identification just because you made a single mistake.