Gestalt plant identification is fast-thinking identification based on the perception of the wholeness of form. Form is not only the size and shape of plant parts but their grouping and patterns that their shapes form in aggregate. Gestalt contrasts with slow-thinking technical identification which examines and compares leaf arrangement, corolla color, fruit shape, and other details of individual parts that can be described clearly in words.
What I describe as “technical” identification has also been described as “analytical,” for example, Jones (2013) combined Gestalt methods and “analysis” methods in the identification of images of sedges (species of the genera Carex, Kobresia, and Cymophyllus). As conceived by Wertheimer in 1923, which emphasized visual perception, the basic idea of Gestalt was that the whole is greater than the sum of its parts.
Gestalt as used here is based on characteristics that may not be able to be put into words. It is how we identify people based on their faces or their gait or their voice, without examining discrete descriptors such as eye color, the presence or absence of facial hair, or the pitch of a person’s voice. In another example of the use of Gestalt in visual identification, Hörhan and Eidenberger (2021) used the Gestalt law of closure in the identification of human faces as part of deep learning. Like artificial intelligence generally, Gestalt seems magical in its speed and sometimes it is accurate. It is my idea that people routinely use Gestalt to identify plants, even without books and herbarium specimens. How else can the average person recognize a palm as a palm (a plant in the family Arecaceae), without a formal description?
One can observe subliminally the general shape of a palm from a distance, or the patterned texture of the canopy, or subtle differences in hue, without even thinking about individual leaves.
Besides being almost instantaneous, Gestalt identification can be performed at a greater distance than technical identification. It is often better to practice Gestalt identification at a distance because the “wholeness of form” is partly contextual in terms of where the plant grows and how it is distributed with its neighbors.
True to the idea of “wholeness of form,” characteristics that are part of Gestalt make sense when viewed in a grouping of repeated elements. For example, the trunks of sabal palms are generally not perfectly vertical but lean, often in different directions. If they were all straight up and down, as a group they would not look like sabals, and one isolated sabal palm would not have the characteristics of a group.
The other natural aspect of Gestalt identification, besides it being the way we first learn many things, is that it embodies the variability within a species. While descriptive characteristics tend to put hard limits on the perimeters of a species, Gestalt is compatible with the flexibility of the “species concept” as a cluster of very similar entities.
Fragrance or scent is an interesting identification tool. But modern humans have an undeveloped vocabulary for fragrances, and we are highly variable and suggestible in our scent sensitivity. Different people describe the fragrance of a plant with very different words, but sometimes fragrance can play upon the senses without being explicitly noted, so scent may be part of Gestalt. Other unseen characteristics can aid in Gestalt identification, such as the sound of bamboo stems creaking and clanking in the wind at night.
The leaves of plants in the family Combretaceae tend to be clustered on the tips of the stems, something which can be described but without discrete thresholds. In the case of green buttonwood, the leaves are also acute and point away from the center of the tree, which gives the ends of the branches a “spiky” appearance.
Gestalt plant identification is learned by practice, for example, by repeatedly looking at plants. Once learned, Gestalt identification is fast and effective in observing and learning unknown specimens within a narrow range of possibilities but can be prone to error. Gestalt identification may be effective in examining plants seen repeatedly within a particular environment, but out of context errors can be made.
Farmers and hunters and people who work outdoors see the most common plants and wildlife repeatedly and become trained to identify them. But gestalt identification may only go so far and may not be scalable to work if the number of species is large or if the outdoors person is transplanted to a different part of the world where different soils affect the growth of plants.
Since gestalt identification is fast but prone to error, and technical identification is slow but potentially accurate, it makes strategic sense to do gestalt first, and then use technical identification to validate identification.
Using two different methods also provides guardrails against making embarrassing mistakes. If you identify a plant by gestalt, then you look it up in a book and compare it based on technical characteristics, you may recognize mistakes in your first hasty attempt.
I worked in Missouri Botanical Garden herbarium when we were processing tens of thousands of plant specimens per year. As a generalist I would toss specimens into groups by family, to be sorted out and identified later to species by specialists who knew the families and could use technical characteristics for species-by-species comparisons.