Department of Biology , University of North Carolina at Greensboro , PO Box 26170, Greensboro, NC 27402 , USA.
AoB Plants. 2011;2011:plr004. doi: 10.1093/aobpla/plr004. Epub 2011 Jan 21.
Although illustrations have played an important role in identification keys and guides since the 18th century, their use has varied widely. Some keys lack all illustrations, while others are heavily illustrated. Even within illustrated guides, the way in which images are used varies considerably. Here, we review image use in paper and electronic guides, and establish a set of best practices for image use in illustrated keys and guides.
Our review covers image use in both paper and electronic guides, though we only briefly cover apps for mobile devices. With this one exception, we cover the full range of guides, from those that consist only of species descriptions with no keys, to lavishly illustrated technical keys. Emphasis is placed on how images are used, not on the operation of the guides and key, which has been reviewed by others. We only deal with operation when it impacts image use.
Few illustrated keys or guides use images in optimal ways. Most include too few images to show taxonomic variation or variation in characters and character states. The use of multiple images allows easier taxon identification and facilitates the understanding of characters. Most images are usually not standardized, making comparison between images difficult. Although some electronic guides allow images to be enlarged, many do not.
The best keys and guides use standardized images, displayed at sizes that are easy to see and arranged in a standardized manner so that similar images can be compared across species. Illustrated keys and glossaries should contain multiple images for each character state so that the user can judge variation in the state. Photographic backgrounds should not distract from the subject and, where possible, should be of a standard colour. When used, drawings should be prepared by professional botanical illustrators, and clearly labelled. Electronic keys and guides should allow images to be enlarged so that their details can be seen.
尽管插图自 18 世纪以来就在鉴定钥匙和指南中发挥了重要作用，但它们的使用方式差异很大。有些钥匙完全没有插图，而有些则大量使用插图。即使在有插图的指南中，图像的使用方式也有很大的不同。在这里，我们回顾了纸质和电子指南中图像的使用情况，并为有插图的钥匙和指南中的图像使用制定了一套最佳实践。
我们的综述涵盖了纸质和电子指南中图像的使用情况，尽管我们仅简要介绍了适用于移动设备的应用程序。除了这一个例外，我们涵盖了从只有物种描述而没有钥匙的指南到大量插图的技术钥匙的所有指南。重点放在图像的使用方式上，而不是指南和钥匙的操作上，其他人已经对其进行了综述。只有当操作影响图像使用时，我们才会涉及操作。
很少有有插图的钥匙或指南以最佳方式使用图像。大多数指南包含的图像太少，无法展示分类变化或特征和特征状态的变化。使用多个图像可以更容易地识别分类单元，并有助于理解特征。大多数图像通常没有标准化，使得比较图像变得困难。尽管一些电子指南允许放大图像，但许多指南不允许。
最好的钥匙和指南使用标准化的图像，以易于查看的大小显示，并以标准化的方式排列，以便可以在不同物种之间比较相似的图像。有插图的钥匙和词汇表应为每个特征状态包含多个图像，以便用户可以判断状态的变化。摄影背景不应分散注意力，并且在可能的情况下，应采用标准颜色。如果使用绘图，则应由专业的植物插图画家绘制，并清楚地标记。电子钥匙和指南应允许放大图像，以便可以查看其细节。
