b. Silique: A slender, dry, dehiscent fruit that superficially resemble a legume, except the mustard silique is composed of two carpels with a partition or septum down the center (i.e. between the two carpels or valves). [The legume fruit is composed of a single carpel and does not have the central partition or septum.] This is the typical fruit of the mustard family (Cruciferae or Brassicaceae). E.g. field mustard, turnip and cabbage (Brassica species), stock (Mathiola), wallflower (Erysimum) and London rocket (Sisymbrium). The silicle is a shortened (less elongate) version of a silique, including sweet alyssum (Lobularia), peppergrass (Lepidium) and shepherd's purse (Capsella). [Note: As with legumes there are a few exceptions to the typical form of siliques and silicles. In wild radish (Raphanus) the silique does not split lengthwise, but instead it breaks transversely into several seed-bearing joints. In lace pod (Thysanocarpus) the silicles are indehiscent.]

c. Capsule: Seed pod splits open is various ways and usually along several definite seams. Capsules typically split open into well-defined sections or carpels which represent modified leaves. This is a very common dry fruit found in many different plant families. E.g. Catalpa, Jacaranda, Pittosporum, Aesculus, Agave, Yucca, Eucalyptus, devil's claw (Proboscidea), floss silk tree (Chorisia), kapok tree (Ceiba) and castor bean (Ricinus communis). Capsules may split open along the locules (loculicidal), along the septa (septicidal), through pores (poricidal), or the entire top of the capsule separates as a single lid-like section (circumscissile). A common landscaping tree in southern California called the golden-rain tree (Koelreuteria) produces bladder-like capsules that are loculicidally dehiscent into three valves. The opium poppy (Papaver somniferum) produces a classic poricidal capsule in which the tiny seeds fall out of the pore-like windows as the capsule shakes in the wind. The edible weed called purslane (Portulaca) has a many-seeded circumscissile capsule. The Mexican jumping bean (Sebastiana pavoniana) produces a 3-carpellate capsule, each carpel bearing a seed. Sometimes the carpel is occupied by a special moth larva that eats the seed and moves its one-room carpel container by contorting and hurling its body. In the liquidambar tree (Liquidambar styraciflua) the globose fruiting heads are composed of numerous tiny capsules, each bearing one or two winged seeds and a number of aborted ovules (immature seeds). It should be noted here that some capsules are indehiscent. Their carpels do not separate and release the seeds. Two examples of plants with indehiscent capsules are the South African baobab tree (Adansonia digitata) and two species of South African gardenias (Gardenia thunbergii and G. volkensii). The seed pods of South African gardenias are chewed opened by large herbivores, and the seeds are dispersed in their feces. Spjut (1994) classifies the unusual fruit of the devil's claw (Proboscidea) as a "ceratium," a capsular fruit that opens by a separation or break in the pericarp layers.

b. Anthocarp: In the four o'clock family (Nyctaginaceae), individual apetalous flowers have a tubular, petaloid calyx that resembles a sympetalous corolla. The lower portion of the calyx tightly enwraps the one-seeded achene and is persistent around the fruit as an anthocarp. The calyx base plus the enclosed seed-bearing achene is the unit of dispersal. In some members of the Nyctaginaceae, the persistent calyx base bears sticky glandular projections that aid in dispersal by adhering to the bodies of animals. This is especially true in pisonia trees (Pisonia umbellifera) in which the numerous glutinous anthocarps stick to the feathers of seabirds. This is an effective method of dispersal to distant atolls and islands of the South Pacific region. Sometimes a hapless seabird is completely covered by clusters of the sticky anthocarps, to the point where flight is difficult or impossible. Unable to remove the water-resistant, glue-like anthocarps from its feathers, the seabird drowns in the surf and is consumed by ravenous beach crabs.

c. Grain or Caryopsis: A very small, dry, one-seeded, indehiscent fruit in which the actual seed coat is completely fused to the ovary wall or pericarp. The outer pericarp layer or husk is referred to as the bran, while the inner, seed layer is called the germ. This is the characteristic fruit of the large grass family (Gramineae or Poaceae). The grain is truly a fruit (not a seed) because it came from a separate ripened ovary within the grass inflorescence. This is the number one source of food for people on the earth. E.g. Corn (maize), wheat, rice, rye, barley, oats, Johnson grass, Bermuda grass and many more species. In corn grains, the main white material that explodes when the grains are heated is endosperm tissue within the seed. Pressure (water vapor) builds up within the grains until they literally explode.

d. Schizocarp: A small dry fruit composed of two or more sections that break apart; however, each section or carpel (also called a mericarp) remains indehiscent and contains a single seed. Because the seed-bearing sections or carpels (called mericarps) do not split open, this type of fruit is usually placed under indehiscent dry fruits. This is the characteristic fruit of the carrot family (Umbelliferae or Apiaceae). E.g. Carrot (Daucus), celery (Apium) and sweet fennel (Foeniculum vulgare). Other examples of schizocarps include filaree or stork's bill (Erodium) and cheeseweed (Malva), two common weeds in southern California. In these weeds, the seed-bearing carpels (mericarps) separate from each other, but remain indehiscent. Gynoecium is a collective term for the carpels of a flower. Biologists commonly refer to this floral unit as a pistil. Monocarpous flowers are composed of one carpel (a simple pistil). The terms apocarpous and syncarpous refer to compound pistils composed of more than one carpel. Apocarpous flowers contain two or more distinct carpels. In syncarpous flowers, two or more carpels are fused together. In cheeseweed, the carpels are attached to a central, conical connection stalk, but separate from this stalk at maturity. Some authors consider the fruit of the maple (Acer) to be a schizocarp because it splits into two indehiscent, seed-bearing carpels; however, because of the wing on each seed-bearing carpel, other botanists refer to maple fruits as double samaras (see the samara fruit).

One of the most painful schizocarps is the puncture vine (Tribulus terrestris). When dry, the spiny fruit splits into indehiscent, seed-bearing sections (carpels). The spines of each section are arranged so that one is always facing upward, like the medieval weapon called a caltrop. The spiny, seed-bearing burs readily penetrate bare feet, shoes and rubber tires.

e. Samara: Small, winged, one-seeded fruit, usually produced in clusters on trees. E.g. Maple (Acer): a double samara, ash (Fraxinus), elm (Ulmus) and tree of heaven (Ailanthus). Samaras resemble the winged seeds of a pine, but they are truly one-seeded fruits with a pericarp layer surrounding the seed. The leguminous tipu tree (Tipuana tipu) has a winged fruit that certainly resembles a samara even though it belongs to the legume family (Leguminosae or Fabaceae). Like auto-rotation of helicopters, the samaras spin as they sail through the air, an effective method of dispersal. Richard Spjut (1994) classifies some of the larger winged fruits of Shorea (Diptocarpaceae) and Gyrocarpus (Hernandiaceae) as a "pseudosamara."

Whirling Nut (Gyrocarpus)

See Samaras Of Box Elder & Maple   See The Winged Fruits Of Tipu Tree See The Winged Fruits Of Ash Tree

f. Nut: Larger, one-seeded fruit with very hard pericarp, usually enclosed in a husk or cup-like involucre. Unfortunately, the above reference by Richard Spjut does not use the term "nut" as a distinct fruit type.