How to: take photographs of plants for identification

Guest post by Kevin Mills

The best technique to obtain good photographs for plant identification is an important consideration for those sending plant photos to others for ID. I must admit that I have received many photos that make it near impossible to identify the species involved. With so many people taking plant photos with their phones, it is timely to set out some guidance. While this is not a photography lesson, I hope that the points below are helpful to those taking plant photos.

What are the key features that need to be shown?

Taking a photo of a plant from 10 metres away and expecting someone to ID it is being a bit too optimistic. Most such photos could only show growth habit at best. Taking a close-up photo only of a single flower may not be much use either. Ideally, the following features should be captured on the photographs of a plant where possible for accurate ID.

• A clear photo of the leaves at a reasonable scale, showing their arrangement (e.g., opposite or alternate), venation, etc. In some species a photo of the underside of the leaf is important and should be included.
• A photo of the flower or flower head should be taken if present, along with the adjoining stems and leaves.
• Fruit come in all sorts of colours, shapes and sizes and may be important for accurate ID. A photo of a fruit or cluster of fruit should be taken if available.

Obviously, all relevant features are unlikely to be present all year round or at the same time, so one needs to make the best of the available features of the plant.

Long distance shots such as this are not much use as an identification aid; compare this shot with the photograph below, both showing a Cheese Tree (Glochidion ferdinandi).

For some species, particular features may be important, such as the bark and capsules of a eucalypt (see photos below). The idea is to provide as much information as possible.

To identify a eucalypt from photographs, images of the bark, leaves and fruit should be provided. For example, Brown Barrel (Eucalyptus fastigata), is readily identified using the below photos.

Providing other information

Additional information on location, habitat, habit and environmental situation can aid identification. Geographic location can quickly eliminate similar-looking species that do not occur in the area. Habit, such as herb or shrub, is always useful information to have. All species grow in a particular environmental setting, such as vegetation type, geology (soil type), altitude and local topography. While such information may not always be essential, it adds to the whole picture that the person asked to identify the plant has available to accurately ID the plant.

Some additional things to keep in mind

The field of view should be considered. As much as possible keep the parts of the plant you wish to highlight in focus by looking for a picture that shows the features more or less in the same plane.

• Consistent light across the frame is best, high contrast across the photo should be avoided (e.g., patches of bright sunlight).
• You do not need to skimp on photos with digital cameras, so take as many as you like and send in only the best ones.
• The use of flash can be helpful in darker situations and to highlight the whole plant in the frame.
• Make sure that the leaves you are photographing are associated with the flowers or fruits in your photos. Having multiple plant species in the shot is a common error that makes it hard to identify the plant in question.
• Remember that some species have compound leaves (e.g., pinnate), so be sure to photograph the whole leaf not just a leaflet.

The following are good photos for identifying a plant.

Narrow-leaved Bottlebrush (Callistemon linearis), showing leaves, flower spike and mature fruit (capsules); the flower colour and the narrow linear leaves clearly identify it as this species.

Cheese Tree (Glochidion ferdinandi), showing leaves and a fruit capsule; the glossy, alternate leaves and distinctive fruit capsule leave no doubt about its identity.

Detail may be important

Some closely-related species (i.e., those in the same genus) can be difficult to identify without attention to particular small details that aren’t obvious to the casual observer. These might be the presence of hairs of different types on stems, leaves or flowers, or the way ferns produce their spore. In these cases, ID from the above types of photographs alone may be inadequate. Learning more about the plants that grow in this region will help you learn what to photograph and perhaps get closer to making an ID yourself.

Sori (aggregates of spore-containing sporangia) on the underside of a part of a frond of Sickle Spleenwort (Asplenium polyodon). Ferns have distinctive arrangements and structures of sori that can assist in identification.

Upper leaf surface (photo above) and lower leaf surface (photo below) of a leaf of Rusty Pomaderris (Pomaderris ferruginea). The type, colour and density of hairs are important features in this genus.

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Kevin Mills is the author of many articles, books and reports on the plants and vegetation of the Illawarra area. His monthly Budawangia newsletter is a great local resource, and you can subscribe by emailing him at kevinmillskma@gmail.com