The term “pod” is commonly used to identify any dry, elongated fruit that hangs from a tree and contains seeds. While botanically specific (referring to the unique fruit structure of the pea family), this fruit-like casing is frequently the easiest way to identify several common tree species throughout the year. Differences in shape, size, and texture of these seed structures provide visual clues to distinguish between similar-looking trees. This guide explores the most common trees known for producing these distinctive seed casings, differentiating between true botanical pods and other look-alike fruits.
Trees That Bear True Legume Pods
A true pod, or legume, is the fruit of a plant in the Fabaceae family (the pea and bean family). This fruit develops from a single carpel and typically splits open along two seams to release its seeds. Several widespread North American trees belong to this family and are easily recognized by their characteristic flattened, bean-like pods.
The Honey Locust (Gleditsia triacanthos) is known for producing strikingly long, ribbon-like pods. These fruits are often twisted or curled and typically range from 7 to 18 inches long, maturing to a dark brown or black color. The pods develop in the late summer and often persist on the tree through the winter, providing a strong visual identifier against a leafless canopy.
The closely related Black Locust (Robinia pseudoacacia) produces significantly smaller, flatter pods. These legumes measure about 2 to 4 inches long and are reddish-brown to dark brown when ripe. Unlike the massive, often-twisted fruit of the Honey Locust, the Black Locust’s pods are smooth and generally remain attached to the branches well into the winter. The contrast in size and shape helps distinguish the two species, which are both widespread in urban and natural areas.
Another member of the legume family is the Eastern Redbud (Cercis canadensis), known for its prolific production of small, flat, bean-like fruits. These pods are slender, typically measuring between 2 and 4 inches in length, and often appear in numerous clusters along the branches. They start green after the spring flowers fade, transitioning to a dry, papery brown or purplish hue as they mature in the late summer and fall. The persistence of these small pods throughout the winter gives the Redbud a distinct, textured look.
Trees with Elongated Seed Capsules
Many trees commonly described as having “pods” are botanically classified as capsules or siliques, not true legumes. These structures are typically elongated and woody or leathery. They differ from true pods in how they split open to release their seeds, but they are included here because their appearance matches the common description of a tree “pod.”
The Catalpa tree (Catalpa speciosa or C. bignonioides) is a noted example, earning common names like cigar tree or Indian bean tree. Its fruit is a long, slender, cylindrical seed capsule that strongly resembles a hanging cigar. These structures are green during the summer, reach 8 to 20 inches long, and mature to a dark brown color in the fall. The capsules often hang on the tree throughout the winter, splitting open lengthwise to disperse their seeds in the late winter or early spring. The seeds inside are numerous, flat, and equipped with thin, papery wings for wind dispersal.
Another tree in this category is the Empress Tree (Paulownia tomentosa), which produces a smaller, woody, pointed seed capsule. These dry, brown fruits measure about 1 to 1.5 inches long and appear in clusters on the branches. The capsules mature in the autumn, opening to release thousands of tiny, winged seeds, but the empty capsules frequently remain attached through the winter.
Visual Identification and Safety Notes
Distinguishing between these seed structures requires observing a few simple characteristics, notably the shape and persistence of the fruit. True legume pods, such as those from locust trees, are distinctly flat and compressed. Capsules, like those of the Catalpa, are cylindrical with a round cross-section, giving them a thick, cigar-like appearance.
Length is another clue: Honey Locust and Catalpa typically produce the longest structures, often exceeding 12 inches. Black Locust and Redbud are characterized by shorter, flatter fruits, generally staying within the 2-to-4-inch range. The tendency of these mature, dried fruits to remain on the tree through the winter makes them useful for identification during colder months.
A serious safety note involves the toxicity of many of these tree parts, especially the seeds. The seeds and other parts of the Black Locust (Robinia pseudoacacia) contain toxic compounds that can cause illness in humans and animals, particularly horses. While the pulp of the Honey Locust’s pod is sweet and non-toxic, the seeds should not be consumed.
It is advisable to treat all seeds and fruits from wild or ornamental trees as potentially harmful unless positively identified as edible by an expert. Ingestion of unknown seeds is strongly discouraged, as even small amounts from trees like the Black Locust can lead to severe gastrointestinal distress.