花冠

花冠（corolla）是一朵花中所有花瓣的總稱，為花部（flower parts）四輪構造的第二輪，絕大多數情況下位於花萼的內側，雄蕊外側。

顏色鮮艷或有氣味的花冠，常用於吸引昆蟲傳播花粉，系對蟲媒的適應。花冠還可發揮對非生物性因素的適應性功能，例如保護花粉免受雨水浸蝕^[1]（朝鮮白頭翁^[2]、珙桐^[3]），紫外線輻射損傷^[4]（部分高山植物^[5]），或乾燥失活（辣木屬^[6]）。花冠的大小和形狀都會對花粉活力的持久性和傳播的效率造成影響^[7]。

形態構造

各個花瓣彼此都完全獨立分離的花冠，稱為離瓣花冠；這種花稱為離瓣花，如：十字形花冠的油菜花。各個花瓣彼此相連癒合或只有基部連接合生在一起的花冠，稱為合瓣花冠；這種花稱為合瓣花，如：牽牛花。合瓣花全部或下部連合的部分稱為花冠筒（corolla tube）；而合瓣花上部分離的部分，稱為花冠裂片（corolla lobe）。

花冠依照其形狀可分為輪狀（Rotate）、壺狀（Urceolate）、鐘狀（Campanulate；桔梗屬等）、筒狀（Tubular）、盆狀（Salverform）、漏斗狀（Funnelform）、舌狀（Ligulate；菊科等）、蝶狀（Papilionaceus；豆科等）、唇形（Labiate；唇形科等）等。

形態構造

^ Mao, Yun‐Yun; Huang, Shuang‐Quan. Pollen resistance to water in 80 angiosperm species: flower structures protect rain‐susceptible pollen. New Phytologist. 2009-08, 183 (3): 892–899. doi:10.1111/j.1469-8137.2009.02925.x.
^ Huang, Shuang‐Quan; Takahashi, Yoshitaka; Dafni, Amots. Why does the flower stalk of Pulsatilla cernua (Ranunculaceae) bend during anthesis?. American Journal of Botany. 2002-10, 89 (10): 1599–1603. doi:10.3732/ajb.89.10.1599.
^ Sun, Ji‐Fan; Gong, Yan‐Bing; Renner, Susanne S.; Huang, Shuang‐Quan. Multifunctional Bracts in the Dove Tree Davidia involucrata (Nyssaceae: Cornales): Rain Protection and Pollinator Attraction. The American Naturalist. 2008-01, 171 (1): 119–124. doi:10.1086/523953.
^ Flint, Stephan D.; Caldwell, Martyn M. INFLUENCE OF FLORAL OPTICAL PROPERTIES ON THE ULTRAVIOLET RADIATION ENVIRONMENT OF POLLEN. American Journal of Botany. 1983-10, 70 (9): 1416–1419. doi:10.1002/j.1537-2197.1983.tb07931.x.
^ Zhang, Chan; Yang, Yong-Ping; Duan, Yuan-Wen. Pollen sensitivity to ultraviolet-B (UV-B) suggests floral structure evolution in alpine plants. Scientific Reports. 2014-03-31, 4 (1). doi:10.1038/srep04520.
^ Vaknin, Yiftach; Eisikowitch, Dan; Mishal, Adina. Floral and Pollen Traits of Moringa oleifera Lam. and Moringa peregrina (Forssk.) Fiori Provide Reproductive Adaptations for Arid Conditions. Agronomy. 2021-05-27, 11 (6): 1090. doi:10.3390/agronomy11061090.
^ Makowski, Hanna; Scott, Emily; Lamb, Keric; Galloway, Laura F. Compensating for the corolla? Pollen exposure is not associated with pollen-collecting hair length. Annals of Botany. 2024-12-31, 134 (6): 1027–1036. doi:10.1093/aob/mcae139.

[1] Mao, Yun‐Yun; Huang, Shuang‐Quan. Pollen resistance to water in 80 angiosperm species: flower structures protect rain‐susceptible pollen. New Phytologist. 2009-08, 183 (3): 892–899. doi:10.1111/j.1469-8137.2009.02925.x.

[2] Huang, Shuang‐Quan; Takahashi, Yoshitaka; Dafni, Amots. Why does the flower stalk of Pulsatilla cernua (Ranunculaceae) bend during anthesis?. American Journal of Botany. 2002-10, 89 (10): 1599–1603. doi:10.3732/ajb.89.10.1599.

[3] Sun, Ji‐Fan; Gong, Yan‐Bing; Renner, Susanne S.; Huang, Shuang‐Quan. Multifunctional Bracts in the Dove Tree Davidia involucrata (Nyssaceae: Cornales): Rain Protection and Pollinator Attraction. The American Naturalist. 2008-01, 171 (1): 119–124. doi:10.1086/523953.

[4] Flint, Stephan D.; Caldwell, Martyn M. INFLUENCE OF FLORAL OPTICAL PROPERTIES ON THE ULTRAVIOLET RADIATION ENVIRONMENT OF POLLEN. American Journal of Botany. 1983-10, 70 (9): 1416–1419. doi:10.1002/j.1537-2197.1983.tb07931.x.

[5] Zhang, Chan; Yang, Yong-Ping; Duan, Yuan-Wen. Pollen sensitivity to ultraviolet-B (UV-B) suggests floral structure evolution in alpine plants. Scientific Reports. 2014-03-31, 4 (1). doi:10.1038/srep04520.

[6] Vaknin, Yiftach; Eisikowitch, Dan; Mishal, Adina. Floral and Pollen Traits of Moringa oleifera Lam. and Moringa peregrina (Forssk.) Fiori Provide Reproductive Adaptations for Arid Conditions. Agronomy. 2021-05-27, 11 (6): 1090. doi:10.3390/agronomy11061090.

[7] Makowski, Hanna; Scott, Emily; Lamb, Keric; Galloway, Laura F. Compensating for the corolla? Pollen exposure is not associated with pollen-collecting hair length. Annals of Botany. 2024-12-31, 134 (6): 1027–1036. doi:10.1093/aob/mcae139.

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