Achene

Article

May 21, 2022

Achene (yes, English: achene, akene, achaenium, achenium, achenocarp) is a type of fruit that has a dry skin that wraps a seed and does not dehiscence. It is often referred to as a "seed" because it looks like a single seed (eg sunflower seeds), but it is actually a fruit that contains a single seed rather than a seed. In a narrow sense, one carpel (leaf element that constitutes the pistil) in the upper part of the ovary (the part of the pistil that contains the ovule that is the source of the seed is attached above the petals and the base of the stamen). ), But usually the lower ovules and those consisting of multiple carpels are also called achene. Those derived from the lower ovary, such as the achene of the Asteraceae family, are also called lower achene (chrysanthemum fruit). Multiple achenes are formed from one flower and may form aggregate fruits. Strawberry-like fruits and rose-like fruits are false fruits that are aggregate fruits consisting of achene and occupy most of the structures derived from the tentacles. In addition, there are also examples of sycamores in which multiple flowers form achene and form complex fruits (multi-flowered fruits) together. Achene does not dehiscence, so seed-containing fruits are sprayed.

Definition

In a narrow sense, it consists of one carpel in the upper part of the ovary, the pericarp is dry in the mature state, and one seed is tightly wrapped, but the pericarp and the seed coat are not coalesced, and the fruit that does not dehiscence It is called achene. Such achene is found in Japanese achene (Urticaceae), Omodaka (Urticaceae; lower figure 1a), Hirumushiro (Hirmushiro family; lower figure 1b), Matsumo (Matsumo family), Umanoashigata, Nirinsou, Senninsou, Karamatsusou (Ranunculaceae; lower figure 1c). , Boehmeria longis, Achene (Urticaceae), Dutch strawberry (Rosaceae; 1d below), Rose, Daikonsou, Ranunculaceae, Yamabuki, Waremokou (1e below) (Rosaceae), Achene (Elaeagnaceae), etc. However, fruits with similar characteristics, even those consisting of multiple carpels, are usually called achene. Such fruits are Koboumugi, Watasuge, Himekugu (Hempaceae; 1g below), Keyaki (Ulmaceae; 1f below), Kuwa, Kuwakusa, Kozo, Inubiwa (Moraceae), Humulus japonicus (Hempaceae; 1g below), Dokutsugi (Hempaceae). ), Suiba, Itadori (1h in the figure below), Inutade (Hempaceae), etc. Fruits of the Asteraceae family such as Noazami, Dandelion (1i above), Solidago altissima, Solidago altissima, Fuki, Hahakogusa, Erigeron annuus, and Sunflower (1j above) are also achene, but lower in the ovary (1j above). Since the ovary is located below the petals and the base of the pistil, and the ovary is surrounded by a tentacle), it is sometimes called lower achene (Asteraceae, cypsela). Lower achene is also found in Valeriana flaccidus, Patrinia scabrioides, and Pincushion flower (honeysuckle). The fruits of the Gramineae family are also a type of achene, but they are peculiar in that the pericarp and seed coat are usually closely bonded and wrapped in a caryopsis or a bract (a bract that wrapped a flower). Therefore, it is especially called caryopsis (grain). Similar to achene and caryopsis, there are nuts and glans as non-dehiscent dried fruits containing one seed, but nuts are distinguished by the fact that the pericarp becomes hard and woody. However, the distinction between achene and nuts is not clear, and fruits of the sedge family and Polygonaceae may be achene or nuts (or small nuts). Also, as non-dehiscence (or dehiscence) dried fruits containing 1 seed, etc.