What Is a Signature?: A Short Introduction to the Ancient Doctrine of Plant Signatures

Printed in the  Winter 2018  issue of Quest magazine. 
Citation: Graves, Julia, "What Is a Signature? A short introduction to the ancient doctrine of plant signatures" Quest 106:1, pg 24-25

By  Julia Graves 

It is a fascinating approach, not only because of the satisfying symmetry of such correspondence, but because generally it is an accurate guide. I adopted the doctrine of signature as a teaching aid in identifying medicinal herbs.
Ben Charles Harris (Harris, 4)

Theosophical Society - Julia Graves trained in Anthroposophic massage therapy, herbalism, and medicine from an early age. Julia has traveled around the world, from North America to the Himalayas, to study the doctrine of signatures. She is a practicing herbalist, a maker of flower essences, and a naturopathic doctor. She organized a naturopathic relief clinic in response to the 2010 earthquake in Haiti.The celebrated physician Paracelsus (1493–1541) saw the doctrine of signature as a proof of how microcosm and macrocosm were analogous—as above, so below. He says in Astronomica magna: “The expert must know how to recognize the virtue of all things thanks to the signs, be it an herb, a tree, a living being, or an inanimate object.” While this thought originates from his alchemical studies, which are pre-Christian, as a devout Christian he concludes by writing that this is because God created things as such, and that he left signs for us to discover the virtues he has hidden in all of creation. It is quite noticeable how, throughout his work, entire passages are free from any Christian notions, while others attribute everything back to a creator God.

To Paracelsus, signatures are the knowledge of the inner essence based on outer characteristics (Jacobi, 53). He said, “Thou shalt know all internal [characteristics] by looking at the outside.” “God does not want things to stay hidden, which He created for mankind’s benefit and which he gave man as his property into his hand.  .  .  .  And even though He Himself hid it, so did He mark upon it outer, visible signs, that are special marks. Not different from One, who buries a treasure and does not leave it unmarked, because he puts a sign onto the spot, so he himself can find it again.” Calling it the “art of signs,” he writes, “As you see, every herb has been brought into the shape that is akin to its inner nature [by God]” (ibid., 169f.). Because of the law of correspondence, the universe is established lawfully enough for him to base his knowledge of medical plants upon it. He writes: “There is a further necessity that you know such shapes in the anatomy of herbs and plants and that you bring them together with the anatomy of the disease. The simile, according to which you should treat, makes healing understandable.” And, “Who writes about the power of the herbs without the signature, is not writing from knowledge. He writes like a blind man” (in Wood, Magical Staff, 21). Thus tumorlike plants such as tree fungi treat tumorlike diseases. Today, the reishi and chaga fungi, for instance, have been proven to have strong anticancer properties. Paracelsus’s definition might be paraphrased this way: “Like colors, shapes, and other characteristics in the plant cure those same or corresponding colors, shapes, and characteristics in the body” or “that which looks like a body part or disease in the plant cures that body part or disease in animals or humans.”

Paracelsus’s law of similes—“like cures like”—applied to herbology, means that a specific characteristic of the plant will cure the thing similar to it in the human body or mind. It looks like what it cures. Likeness or similarity here are ways of talking about the analogy contained in the doctrine of signature.

Paracelsus saw the innermost essence or essential properties of a substance as something like a secret. It was not secret in the sense of something one has not been told, but of something ineffable, beyond words. Who or what we ultimately are cannot be expressed in our limited language, and trying to put labels to it brings us away from the secret—the truth (ibid., 25). Unlike his contemporaries, he did not believe in the rational or analytical way of matching correspondences, such as curing the right eye of a human with the right eye of an animal. This did not work, because it was not in keeping with natural magic. His transrational magic of healing with natural substances meant that a flower with a luminous look, such as eyebright, something that was not an eye but eyelike—could, by way of that correspondence, cure the eyes as if by magic. Eyebright is one of the most efficient remedies for conjunctivitis.

The doctrine of signature is the practical application of the doctrine of correspondence. It is also the practical application of the law of contraries, since the signature of the plant, its quality, can be matched with the signature of the disease either by way of correspondence or by way of contrariness. While this might seem confusing and contradictory, it is not when one understands that the law of action and reaction as a healing principle encompasses both of these seemingly opposite laws.

Although one can say that the doctrine of signature is the applied form of the law of correspondences, one could also say in reverse that the doctrine of signature is the ancient foundation for the law of correspondences. The more modern version is the homeopathic like-cures-like based on the pathology created by a poison. While to Paracelsus, “it looks like what it cures,” Samuel Hahnemann, the founder of homeopathy, took the law of similarity to mean “it causes what it cures.”

The contemporary herbalist Matthew Wood explains that signatures represent configurations of energy or patterns—archetypes—in plants, and that these correspond to similar patterns in people. “We are not looking here for superficial resemblance, but for one that operates on the level of essence,” beingness (Wood, Herbal Wisdom, 21f). “The law of correspondence, the doctrine of signature, and the law of similars point to the existence of a core essence, configuration, or identity-pattern at the root of every natural substance” (Wood, Magical Staff, 25). He sees true signatures as more profound and magical if they are less rational, in keeping with Paracelsus’s understanding of natural magic. Ferns do not really look like spleens, yet their leaf pattern is the spleen signature, and that holds true like magic even in nonferns, such as sweetfern (Comptonia) or even wood betony. 

  Theosophical Society - The doctrine of signature is the practical application of the doctrine of correspondence. It is also the practical application of the law of contraries, since the signature of the plant, its quality, can be matched with the signature of the disease either by way of correspondence or by way of contrariness. Wood betony. Plant signatures.
  Wood Betony

I would define a signature of a plant as a characteristic that can be detected by one of the senses—the eyes, ears, nose, tongue/taste, tactile sensation—in concert with the mind giving it meaning. These give rise in turn to the signature of the colors and shapes, of the sounds, smells, and the taste pharmacology so well developed in ancient Western as well as Indian and Chinese herbalism. Unbiased, skillful observation of nature is crucial. It does not extend to the molecular structure of the plant tissue, since to identify this in the scientific sense, we would need a microscope and other gadgets in a laboratory. The doctrine of signature is in this sense prescientific—positively so. It is a shortcut to plant knowledge when we do not want to wait for decades for the lab results, most of which become distorted by looking at isolated substances rather than at the vast orchestra of molecules playing in concert inside of herbal tissue. The molecular signature is not part of our direct experience of the plant. It is a mental construct that we reach with the help of technology, and that we believe based on scientific authority. Instead of anthroquines, we taste bitter and see yellow. Bitter and yellow is the signature, “anthroquines” a mental construct. However, we will not be surprised to find heart glycosides in a plant with such a strong and unmistakable heart-healing plant signature as foxglove or lily of the valley. I see the molecular structure as the expression of the signature on the molecular level. If we are right that the macrocosm resembles the microcosm, such as a characteristic of a planet and a plant, then it should also apply to the next levels down, as in the plant and their cells—and so it does.

We are entering an era when things are understood within the context of their energy or energetic fields. In this view, the doctrine of signature is the recognition that similar energetic patterns give rise to similar shapes and unfoldment in two different things—in this case, a plant or plant part, and a person or body part/mind-set. This is the correspondence of energetic pattern. It is with this in mind that we understand why the big, heavy peony buds that in their spherical compactness look so like a skull with sutures will yield a medicine for trauma to this hard, dense, heavy body part—especially helping to open up the blocked sutures, as verifiable in sacrocranial treatment.

My Haitian folk herbalist friend Jacquelin Guiteau put it succinctly: “The doctrine of signature is how the medicinal plants introduce their healing powers to the healer.” So it is, above all, a means of communication, a language.

A Poetic Language

The doctrine of signature is really a poetic language describing a multidimensional reality in which different facets of signature are simultaneously true, and in which the interplay of the countless elements cannot be exhaustively and finally interpreted. Since it is the human mind that gives meaning to nature, naturally the signatures and their categories shift from one cultural context to another, one adding to the other without contradiction but rather contributing another piece to the larger picture. I was challenged by my brother, who was thoroughly trained in natural science, when trying to explain to him the doctrine of signature: “But if you say that a mushroom growing on a tree is like a cancerous tumor, then, because a mushroom has mycelia, the tumor should therefore have them too.” I did not know what to reply in the moment, although an easy misunderstanding might assume that we are in the realm of mathematics, where if A equals B, then therefore B equals A. We are, however, in the realm of similars. If something is similar, it is not the same. There is a corresponding underlying principle, but the two corresponding things are not identical. The mushroom reaches out via mycelia, the tumor via chemical signals. If they were the same, they could not be a plant on the one hand and a human disease on the other. So since the doctrine of signature helps to draw parallels between a plant and a human condition, it can never be a pair of identical things. It can only be similar. We are entering a realm of analogies, and sometimes our modern minds have become so attuned to natural science that we lose sense of what an analogy is—it serves to make the point by one or more parallels, but if stretched too far, it will stop working. We should therefore always remember that the doctrine of signature is in the truest sense an art, and not a science reducible to mathematical formulas. As much as it is an art, it is also a science of observation in the sense that Johann Wolfgang von Goethe formulated for his approach to natural science. It was his idea, later promoted by Rudolf Steiner, that we should train our senses to a point where our mental force of observation of nature becomes like an organ.

The art of interpreting poetry means that there is never just one meaning, and that one can never find all the meanings. It would be impossible, for instance, to make a complete list of all the possible interpretations of Goethe’s Faust. In poetry, while a word might appear in the line, and the meaning of the word by itself is such and such, we might expect it to take the same meaning in the context of that very line. It is the beauty of the oscillating imprecision of language that the context, intonation, diacritical marks used, and even background of the listener can alter the meaning of that very word. In the same manner, the context in which one doctrine occurs in a plant with regard to its other characteristics can alter or override its meaning. In that sense, the doctrine of signature is an art of interpretation of the direct encounter with the plant, making thorough use of the associative function of the brain that fully engages both of its halves.

Within poetry, the same word or grammatical structure does not always mean the same thing. Depending on the context, the same word will mean different things in different lines. Similarly, yellowness in a flower will mean different things in different plants. In Oregon grape it means that it is a liver-healing plant; in dandelion, that it heals the solar plexus with its associated fear and power issues; in yellow day lily it means that it bestows happiness and joy, dispelling depression; and in sunflower it means that it strengthens the inner sun archetype, the inner father.

Being a poetic language, signature is also sometimes cryptic—it escapes us. We do not understand. It is too profound yet for us to decipher. It is not only a foreign language to learn, it is also a language that requires us to change our minds: to the degree that we still our mind chatter and become calm, allowing nature to talk to us, we will understand more clearly. To the degree that we tune more into nature herself, she will speak up.

Herbalist David Winston considers the doctrine of signature part of something much larger that he calls the “language of plants.” He regards the doctrine of signature as we know it as the last remnant of the European tradition of the language of plants, which includes as its physical aspect the doctrine of signature, then knowledge of the plant’s personality, and finally of its “isness.” This can only be known through well trained intuition, in direct communication with the plant. These three aspects together make up the full language of plants. I would add that the language of plants is part of the larger language of nature, which includes geomancy, palmistry, and face reading. The same principles can be used to decode the underlying characteristics of anything in nature, including landscapes, minerals and stones, animals, and humans.

Art and poetry engage the right brain, while science uses the left. The doctrine of signature is a thoroughly holistic approach, engaging both brain halves. In our analytical culture, “it’s a mystery” means that it cannot be understood or known. However, as Wood suggests in his book The Magical Staff (ix), mystery can communicate—not to the analytical mind, but to the holistic view, to intuition. What mystic and cryptic really mean is that we have not yet found words in the realm of duality to describe it. Thus nature and plants’ unfolding can never be pinned down in one finite definition of the truth, but will remain forever mystical and elusive, forever spurring us on to new visions of multidimensional layers of truth from a realm beyond words.

The Grammar Rules

Besides being a poetic language, signature is similar to the language of dreams in that there can be no negations—no “yes, but” and so on. Interestingly, Native Americans sought to acquire plant knowledge in dreamtime. It is a language of associated characteristics, all of which are a flow of simple, straightforward, positive statements: “I am like this and this and that,” simultaneously true all at the same time. In this language, adjectives play the main role: “I am soft, straight, yellow, cool, and bitter.” “I like humid, acidic soil.” So it is really those adjectives we should pay attention to. If in tuning into a tree someone comes up with “I just feel beauty, simply beauty,” then this is a good hint that one has tuned into something other than the plant itself—perhaps the abstract idea of beauty or love and light. Sometimes, instead of tuning into the plant and its essence, we tune into this something else, such as the landscape or the atmosphere of the moment. For instance, stately trees in general emit a sense of serenity and peace. That is due to their size and age, and is not specific to the tree species. While it is all right to get a sense of peace from tuning into a plant in true plant attunement, signature would not stop there, but would be precise and qualify the sense of peace. Sedating healing plants, or relaxing nervines, can bestow this feeling. So it can feel like “peaceful, cooling,” or “peaceful, relaxing.” Plants are not abstract. Not “out there.” They are earthy, juicy, and real. Right here!

These positive statements can seem to be contradictions. A plant such as nasturtium might be shade-loving and watery, thus cooling, and at the same time pungent in taste and warming. Cooling and warming are contradictory, but here the plant is saying that it contains both these in harmony. It can teach us about maintaining moderate warmth while staying moist.

Another example is the inflated seedpod of Lobelia inflata. It has been taken as a signature for the alveoli inflated in an asthma attack, or as having the form of a stomach. Being a stomach and being alveoli are contradictory, but looking similar in shape to both of them is not. Hence lobelia continues to be an excellent herbal remedy for both asthma and ills of the stomach.

In this context, it is worth pointing out that in holistic case taking as well as in psychotherapy, it is precisely those adjectives our clients use to describe their conditions—“I am heartbroken, discouraged, and down”—that are the most noteworthy things they are telling us, since it is these that will lead us to the right remedy. Thus we ask: how do you feel? It is telling that this very description of subjective symptoms is given no value in orthodox medicine (whose language abounds with nouns: “proliferation of streptococci in the trachea,” etc.).

The truth about nature is multidimensional and multifaceted. So whenever we find ourselves becoming dogmatic about it being only one way or another, we can be sure that we have fallen away from the ultimate truth about Mother Nature, who simply cannot be pigeonholed.

The Rules of Communication

The first rule is that you can only hear what you allow to filter through the constant chatter of your mind. Meditators trained in stilling and calming the ongoing flow of inner talk are very good at perceiving what is out there in a calm, unbiased manner.

The second rule is that we can perceive correctly only what does not get distorted by our layer of neuroses. It is well known in psychotherapy that any neurosis we might have will distort the inner messages we receive. A simple example is a woman who got very upset and offended at the mere sight of a calla lily, calling it “an ugly monkey penis.”

Theosophical Society - The doctrine of signature is the practical application of the doctrine of correspondence. It is also the practical application of the law of contraries, since the signature of the plant, its quality, can be matched with the signature of the disease either by way of correspondence or by way of contrariness. Calla Lily. Plant signatures.  
 Calla lily  

She had been sexually abused. Our neuroses quite literally become colored glasses through which we see the world—it would be best to at least know we had them on our nose, and better still to know which color they were.

The third rule is to let reasoning and interpretation come only after the direct communication with the plant; before or during it will cut the communication. This requires some mental effort. It is to restrain ourselves, once we have found the slightest inkling of a signature, from running and writing it down and talking about it, rather than staying with the experience and let it unfold.

The fourth rule is that we forget when we go from one mental state to another. It is commonly known that people remember what they experienced while drunk when they become drunk again, but not while sober. We suddenly remember last night’s dream when slipping into sleep the next night. In the same way, as we “go under” into a meditative state to do the plant attunement, we tend to forget the images and message as we come out of that state back into our everyday mind. It is therefore helpful to learn to come across the threshold slowly and mindfully in order to avoid interrupting the link of memory.

Thus, the calmer, clearer, and more unbiased you are, the better. For a long time, I tried not to read anything about a healing plant before I went to sit with it to feel its essence. I found that not having read other people’s comments left my mind fresh and free. In Zen Buddhism, this is called beginner’s mind. Afterward it was also very helpful to go back and check my findings against those of others, to see how much overlap there was. It is a way of checking back later with oneself about whether one is indeed tuning into the plant and reading the signature, or just tripping. This all ties in with the principle known in psychological testing, as well as quantum physics, according to which the observer, especially the observer’s intention, influences the outcome of the experiment, and further, that objects under observation, even inanimate objects such as electrons, behave differently under observation than when not observed.

“The doctrine of signatures operates through at least two different subjective faculties, the intuition and the imagination” (Wood, Herbal Wisdom, 23). He explains the difference as follows: intuition is the ability to see patterns in the world; imagination is the ability to see images.

Ayurveda takes this into the context of direct yogic perception, a kind of insight gained based on perfect concentration, a completely still mind with an unmoving focus, a state in which the observing mind and the observed object are said to merge into union like water poured into water (Gyatso, 31ff). “The human being transmutes life into consciousness through perception. Through direct perception, the seer is the seen, the observer the observed” (Frawley and Lad, 5).

The sages of ancient India approached healing and herbs with this same consciousness [of total communion with the plant]. Theirs was not a science of experimentation, but a form of direct participation. Experimentation implies distance, a division between the observer and the observed, subject and object. As a result, it is mediated, measured, translated. In dissecting the corpse, the penetration of the soul is missed. Direct perception, or meditation, is the science of yoga. Yoga allows the essence, the thing-in-itself, to disclose itself. When this happens, a full revelation of material and spiritual potential occurs.

The seers, through the yoga of perception, let the plants speak to them. And plants disclose their secrets—many of which are far subtler than a chemical analysis would uncover. Approaching plants in the same way today, not as objects for self-aggrandizement but as integral parts of our own unity, the true value of a plant will flourish for our unselfish use.

To become a true herbalist, therefore, means to become a seer. This means to be sensitive to the being of the herbs, to commune in receptive awareness with the plant-light of the universe. It is to learn to listen when the plant speaks, to speak to the plants as another human being, and to look upon it as one’s teacher.(ibid., 5f.)

The Universal Language

In a realm free from human culture and from language stuck in the limitations of dualism, we can imagine a world made from energy—in the physical sense of its definition, as something immaterial that functions to do work. Energy has received all kinds of labels through the ages and times—the Chinese call it chi, the Indians prana or vayu; it has been called life force in the West and medicine power by the northern Native Americans. It matters little what it is called—it is the dynamic, immaterial aspect of life that propels things, making them function. It is the difference between a living body and a corpse, a live herb and a dried one. In Ayurveda, prana or vayu (wind), as it is called, is said to be the flow of energy that courses the body in set patterns, in part following the nerves and blood vessels, and which propels physiological functions, such as breathing, urination, or blood circulation. It is called wind to illustrate its transmaterial nature as well as its dynamism and mobility. In traditional Chinese medicine, chi and blood are said to be like two sides of a coin, that is, they go together. So the flow of blood and the flow of chi are coupled, again giving chi a dynamic, nonmaterial aspect. Greek humoral medicine thought of the humors or body liquids in a similar fashion, and this is how holistic practitioners of today use the term energy. Energy language is becoming a universal language and an accepted principle, surprisingly uniting such disciplines as quantum physics and chakra healing.

In this universal language of energy, we find that we can establish the doctrine of signature based on a universally observable correspondence of underlying energy patterns and their development.

These can occur at any level: ginseng roots looking like little persons and therefore being the supreme tonic for humankind as a whole; resins oozing out of injured barks, healing and sealing them, hence being powerful antiseptic wound healers; wild snapdragon with yellow flowers shaped like huge jaws helping with digestion and temporomandibular joint disorder (TMJ: tight jaws and teeth grinding).


Frawley, David, and Vasant Lad. The Yoga of Herbs: An Ayurvedic Guide to Herbal Medicine. Santa Fe, N.M.: Lotus Press, 1986.

Gyatso, Lobsang. Lorig Nyerkho Kun Tu [blo rigs nyer mkho kun btus]. Dharamsala, India: Institute of Buddhist Dialectics, 1998. A Mahayana Buddhist monastic text on cognitional theory.

Harris, Ben Charles. The Compleat Herbal: Being a Description of the Origins, the Lore, the Characteristics, the Types, and the Prescribed Uses of Medicinal Herbs, Including an Alphabetical Guide to All Common Medicinal Plants, 2nd ed. New York: Bell, 1985.

Jacobi, Jolande. Paracelsus: Arzt und Gottsucher an der Zeitenwende. 2nd rev. ed. Olten, Germany: Walter, 1991.

Wood, Matthew. The Magical Staff: The Vitalist Tradition in Western Medicine. Berkeley, Calif.: North Atlantic, 1992.

——. The Book of Herbal Wisdom: Using Plants as Medicines. Berkeley: North Atlantic, 1997.

JULIA GRAVES grew up in Germany in close communion with nature. She trained in Anthroposophic massage therapy, herbalism, and medicine from an early age. Julia has traveled around the world, from North America to the Himalayas, to study the doctrine of signatures. She is a practicing herbalist, a maker of flower essences, and a naturopathic doctor. She organized a naturopathic relief clinic in response to the 2010 earthquake in Haiti and presently lives on her farm in France. This article and the accompanying illustrations are excerpted from her book The Language of Plants: A Guide to the Doctrine of Signatures (Lindisfarne Books, 2012) and reprinted with the kind permission of Lindisfarne Books.


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