A botanical plate is not a painting of a plant. It is a page of information about a plant, organized so that a reader can identify the species and understand how it is built, arranged so that the page is also pleasing to look at. Both halves matter. A plate that is scientifically complete but cluttered fails as an illustration; one that is beautiful but omits the fruit fails as a document. The conventions below have evolved over three centuries to satisfy both, and they are worth learning before you decide where to break them.

The Habit Drawing

The central element of most plates is the habit — a drawing of the whole plant, or a representative portion of it, showing how it grows: the stem's posture, the leaf arrangement, the position of flowers, the overall gesture. For a small herb this may be the entire plant including roots; for a shrub or tree it is a characteristic branch with foliage and flowers. The habit is drawn at a stated scale, usually life size or a simple reduction, and it is the drawing the eye goes to first.

The habit should show the plant as it lives. A specimen relaxes when cut; leaves droop, the stem straightens or sags. Refer to your field notes and photographs from before collection, and draw the posture the plant held in the ground. The Botanical Gesture Lab exists largely for this: short timed studies of living specimens train the eye for gesture in a way that studio drawing from cut material cannot.

Stages of the Life Cycle

A single moment rarely tells the story. Most plates include several stages, either within the habit drawing (a stem carrying bud, open flower, and developing fruit) or as separate elements: a bud, a flower at full anthesis, a flower going over, a fruit, a seed, sometimes a seedling. Which stages to include depends on which are diagnostic — for a mustard, the fruit shape is the character; for a columbine, the spurred flower; for a grass, the spikelet. The illustrator's judgment about what to include is itself botanical knowledge, and it is worth asking a botanist, or a good flora, what the identifying characters of the species are before planning the plate.

Details and Dissections

Around the habit sit the details: elements drawn at magnification to show what the habit cannot. Conventionally these include a single flower from the front and side; a longitudinal section showing ovary position and stamen attachment; a single stamen and a single pistil; a cross-section of the ovary or fruit; a seed; a leaf surface or margin at magnification if texture or teeth are diagnostic; and any distinctive structure — a spur, a stipule, a ligule, a bract. The flower anatomy guide covers what each of these should show.

Each detail carries its own scale — a written magnification or a scale bar — because it is at a different scale from the habit. Details are traditionally arranged around the habit in a way that flows: the whole flower, then its section, then its parts, in a reading order that goes from large to small. Numbered or lettered labels keyed to a caption are the scientific convention; in a portfolio piece, small italic labels beside each element serve the same purpose.

Scale, Labels, and the Caption

The plate needs, somewhere, the species name (Latin binomial, italicized, with the family if the convention of the publication asks for it), the scale of the habit, the magnification of each detail, and — for a plate with documentary value — the collection data: where, when, by whom. In publication, most of this goes in a caption below the plate; on a portfolio piece or exhibition work, the binomial and scale usually appear in small lettering at the bottom of the sheet, and the collection data on the back. See measuring a specimen for scale bar practice.

Layout

The sheet is usually portrait, in a standard proportion, with generous margins. Within it:

• The habit dominates. It takes the largest area and is placed slightly off-center, with the plant's natural growth direction — typically upward and slightly to one side — giving the page a diagonal.
• Details are grouped, not scattered. A column down one side, or a cluster in one corner, keeps them from competing with the habit. Their combined visual weight should balance the habit's mass across the page.
• Roots, if shown, sit at the bottom; flowers and fruits, at the top. The page reads as the plant grows.
• White space is part of the design. A crowded plate is hard to read. If the elements do not fit with air around them, the plate needs a second sheet, not a smaller habit.
• Overlap is allowed within the habit — leaves crossing the stem, a flower in front of a leaf — because that is how plants are; but details should not overlap each other or the habit.

Plan the layout on tracing paper before touching the good sheet. Draw each element on its own scrap at its final size, cut them out, and move them around until the page balances. This is standard practice in scientific illustration and it saves ruined sheets.

Traditional Plate Types

A few recognizable formats recur. The flora plate — habit plus a full set of dissections, black and white, for a taxonomic work — is the most rigorous. The Curtis's Botanical Magazine plate — a color habit with a few details, more painterly, with the plant often shown in a cultivated form — is the model for most exhibition botanical art. The herbarium-style plate presents the plant pressed-flat, as if mounted. The life-cycle plate arranges the stages as a sequence around the page. Knowing which you are making decides what goes on it.

Scientific Plate versus Botanical Painting

The distinction is not medium or skill but purpose. A botanical painting may show one gorgeous flower in raking light with a dramatic shadow and no details, and be a wonderful painting. A scientific plate shows the diagnostic characters, at known scale, under conventional light, with details — and can also be wonderful. Many working illustrators do both, and the discipline of the plate improves the painting: an artist who knows where the ovary sits paints the flower more convincingly even when the ovary is not shown. Decide which you are making before you start, and do not let a plate drift into a painting halfway through because the flower was pretty.

A Planning Sequence

1. Identify the species and read what its diagnostic characters are.
2. Decide the stages and details the plate needs to show those characters.
3. Measure the specimen and record the sheet (see measuring).
4. Draw the perishable elements first — the flowers, sections, and dissections — on separate sheets.
5. Draw the habit.
6. Lay out all elements as cut-outs; settle the composition.
7. Transfer to the final sheet and render, lit from the upper left, in the chosen medium (see choosing a medium).
8. Add scale bars, labels, and the binomial. Check every count against the specimen.

It is a slower way to make a picture of a plant. It is the only way to make a plate.