{"id":598,"date":"2018-01-18T19:48:42","date_gmt":"2018-01-18T19:48:42","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/chapter\/flower-structure\/"},"modified":"2024-04-26T18:24:10","modified_gmt":"2024-04-26T18:24:10","slug":"flower-structure","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/chapter\/flower-structure\/","title":{"raw":"Flower Structure","rendered":"Flower Structure"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Describe the components of a complete flower<\/li>\r\n<\/ul>\r\n<\/div>\r\nFlowers contain angiosperm reproductive structures. A typical flower has four main parts\u2014or whorls\u2014known as the calyx, corolla, androecium, and gynoecium (Figure 1).\r\n\r\n[caption id=\"attachment_2116\" align=\"aligncenter\" width=\"604\"]<img class=\"wp-image-2116\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18194834\/Figure_32_01_02.png\" alt=\"Illustration shows parts of a flower, which is called the perianth. The corolla is composed of petals, and the calyx is composed of sepals. At the center of the perianth is a vase-like structure called the carpel. A flower may have one or more carpels, but the example shown has only one. The narrow neck of the carpel, called the style, widens into a flat stigma at the top. The ovary is the wide part of the carpel. Ovules, or megasporangia, are clusters of pods in the middle of the ovary. The androecium is composed of stamens which cluster around the carpel. The stamen consists a long, stalk-like filament with an anther at the end. The anther shown is tri-lobed. Each lobe, called a microsporangium, is filled with pollen.\" width=\"604\" height=\"643\" \/> Figure 1. The four main parts of the flower are the calyx, corolla, androecium, and gynoecium. The androecium is the sum of all the male reproductive organs, and the gynoecium is the sum of the female reproductive organs. (credit: modification of work by Mariana Ruiz Villareal)[\/caption]\r\n\r\nThe outermost whorl of the flower has green, leafy structures known as sepals. The sepals, collectively called the calyx, help to protect the unopened bud. The second whorl is comprised of petals\u2014usually, brightly colored\u2014collectively called the corolla. The number of sepals and petals varies depending on whether the plant is a monocot or dicot. In monocots, petals usually number three or multiples of three; in dicots, the number of petals is four or five, or multiples of four and five. Together, the calyx and corolla are known as the <b>perianth<\/b>. The third whorl contains the male reproductive structures and is known as the androecium. The <b>androecium<\/b> has stamens with anthers that contain the microsporangia. The innermost group of structures in the flower is the <b>gynoecium<\/b>, or the female reproductive component(s). The carpel is the individual unit of the gynoecium and has a stigma, style, and ovary. A flower may have one or multiple carpels.\r\n\r\nIf all four whorls (the calyx, corolla, androecium, and gynoecium) are present, the flower is described as complete. If any of the four parts is missing, the flower is known as incomplete. Flowers that contain both an androecium and a gynoecium are called perfect, androgynous or hermaphrodites. There are two types of incomplete flowers: staminate flowers contain only an androecium, and carpellate flowers have only a gynoecium (Figure 2).\r\n\r\n[caption id=\"attachment_2117\" align=\"aligncenter\" width=\"452\"]<img class=\"wp-image-2117\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18194837\/Figure_32_01_03.jpg\" alt=\"Illustration shows parts of a corn plant. Pistillate flowers are tiny flowers that cluster in strands to form the tassel at the top of the plant. Pollen grains are small, teardrop-shaped structures. Carpellate flowers are clustered in the immature ear, which is covered by leaves. Silk protrudes from the tops of the leaves covering the flower. In the mature ear, the kernels form where the carpellate flowers were located.\" width=\"452\" height=\"661\" \/> Figure 2.\u00a0The corn plant has both staminate (male) and carpellate (female) flowers. Staminate flowers, which are clustered in the tassel at the tip of the stem, produce pollen grains. Carpellate flower are clustered in the immature ears. Each strand of silk is a stigma. The corn kernels are seeds that develop on the ear after fertilization. Also shown is the lower stem and root.[\/caption]\r\n\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Question<\/h3>\r\nIf the anther is missing, what type of reproductive structure will the flower be unable to produce?\r\n\r\n[practice-area rows=\"2\"][\/practice-area]\r\n[reveal-answer q=\"261989\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"261989\"]Pollen (or sperm)\r\n\r\n[\/hidden-answer]\r\n\r\nWhat term is used to describe an incomplete flower lacking the androecium?\r\n\r\n[practice-area rows=\"2\"][\/practice-area]\r\n[reveal-answer q=\"261988\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"261988\"]Carpellate\r\n\r\n[\/hidden-answer]\r\n\r\nWhat term describes an incomplete flower lacking a gynoecium?\r\n\r\n[practice-area rows=\"2\"][\/practice-area]\r\n[reveal-answer q=\"261987\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"261987\"]Staminate[\/hidden-answer]\r\n\r\n<\/div>\r\nIf both male and female flowers are borne on the same plant, the species is called monoecious (meaning \u201cone home\u201d): examples are corn and pea. Species with male and female flowers borne on separate plants are termed dioecious, or \u201ctwo homes,\u201d examples of which are <em>C. papaya<\/em> and <em>Cannabis<\/em>. The ovary, which may contain one or multiple ovules, may be placed above other flower parts, which is referred to as superior; or, it may be placed below the other flower parts, referred to as inferior (Figure 3).\r\n\r\n[caption id=\"attachment_2119\" align=\"aligncenter\" width=\"1024\"]<img class=\"size-large wp-image-2119\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18194840\/Figure_32_01_04-1024x313.jpg\" alt=\"Part A shows a lily, which has an ovary above the petals. The ovary sits above the teardrop-shaped petals. Part B shows several fuchsia flowers hanging down from a stem. The ovary is below the edge of the petals.\" width=\"1024\" height=\"313\" \/> Figure 3.\u00a0The (a) lily is a superior flower, which has the ovary above the other flower parts. (b) Fuchsia is an inferior flower, which has the ovary beneath other flower parts. (credit a photo: modification of work by Benjamin Zwittnig; credit b photo: modification of work by \"Koshy Koshy\"\/Flickr)[\/caption]\r\n\r\n<iframe src=\"https:\/\/lumenlearning.h5p.com\/content\/1291236404452658868\/embed\" width=\"1088\" height=\"637\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><script src=\"https:\/\/lumenlearning.h5p.com\/js\/h5p-resizer.js\" charset=\"UTF-8\"><\/script>\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/8da14a10-9030-46b9-8968-94f3f4fe4115\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Describe the components of a complete flower<\/li>\n<\/ul>\n<\/div>\n<p>Flowers contain angiosperm reproductive structures. A typical flower has four main parts\u2014or whorls\u2014known as the calyx, corolla, androecium, and gynoecium (Figure 1).<\/p>\n<div id=\"attachment_2116\" style=\"width: 614px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2116\" class=\"wp-image-2116\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18194834\/Figure_32_01_02.png\" alt=\"Illustration shows parts of a flower, which is called the perianth. The corolla is composed of petals, and the calyx is composed of sepals. At the center of the perianth is a vase-like structure called the carpel. A flower may have one or more carpels, but the example shown has only one. The narrow neck of the carpel, called the style, widens into a flat stigma at the top. The ovary is the wide part of the carpel. Ovules, or megasporangia, are clusters of pods in the middle of the ovary. The androecium is composed of stamens which cluster around the carpel. The stamen consists a long, stalk-like filament with an anther at the end. The anther shown is tri-lobed. Each lobe, called a microsporangium, is filled with pollen.\" width=\"604\" height=\"643\" \/><\/p>\n<p id=\"caption-attachment-2116\" class=\"wp-caption-text\">Figure 1. The four main parts of the flower are the calyx, corolla, androecium, and gynoecium. The androecium is the sum of all the male reproductive organs, and the gynoecium is the sum of the female reproductive organs. (credit: modification of work by Mariana Ruiz Villareal)<\/p>\n<\/div>\n<p>The outermost whorl of the flower has green, leafy structures known as sepals. The sepals, collectively called the calyx, help to protect the unopened bud. The second whorl is comprised of petals\u2014usually, brightly colored\u2014collectively called the corolla. The number of sepals and petals varies depending on whether the plant is a monocot or dicot. In monocots, petals usually number three or multiples of three; in dicots, the number of petals is four or five, or multiples of four and five. Together, the calyx and corolla are known as the <b>perianth<\/b>. The third whorl contains the male reproductive structures and is known as the androecium. The <b>androecium<\/b> has stamens with anthers that contain the microsporangia. The innermost group of structures in the flower is the <b>gynoecium<\/b>, or the female reproductive component(s). The carpel is the individual unit of the gynoecium and has a stigma, style, and ovary. A flower may have one or multiple carpels.<\/p>\n<p>If all four whorls (the calyx, corolla, androecium, and gynoecium) are present, the flower is described as complete. If any of the four parts is missing, the flower is known as incomplete. Flowers that contain both an androecium and a gynoecium are called perfect, androgynous or hermaphrodites. There are two types of incomplete flowers: staminate flowers contain only an androecium, and carpellate flowers have only a gynoecium (Figure 2).<\/p>\n<div id=\"attachment_2117\" style=\"width: 462px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2117\" class=\"wp-image-2117\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18194837\/Figure_32_01_03.jpg\" alt=\"Illustration shows parts of a corn plant. Pistillate flowers are tiny flowers that cluster in strands to form the tassel at the top of the plant. Pollen grains are small, teardrop-shaped structures. Carpellate flowers are clustered in the immature ear, which is covered by leaves. Silk protrudes from the tops of the leaves covering the flower. In the mature ear, the kernels form where the carpellate flowers were located.\" width=\"452\" height=\"661\" \/><\/p>\n<p id=\"caption-attachment-2117\" class=\"wp-caption-text\">Figure 2.\u00a0The corn plant has both staminate (male) and carpellate (female) flowers. Staminate flowers, which are clustered in the tassel at the tip of the stem, produce pollen grains. Carpellate flower are clustered in the immature ears. Each strand of silk is a stigma. The corn kernels are seeds that develop on the ear after fertilization. Also shown is the lower stem and root.<\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Practice Question<\/h3>\n<p>If the anther is missing, what type of reproductive structure will the flower be unable to produce?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"2\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q261989\">Show Answer<\/span><\/p>\n<div id=\"q261989\" class=\"hidden-answer\" style=\"display: none\">Pollen (or sperm)<\/p>\n<\/div>\n<\/div>\n<p>What term is used to describe an incomplete flower lacking the androecium?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"2\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q261988\">Show Answer<\/span><\/p>\n<div id=\"q261988\" class=\"hidden-answer\" style=\"display: none\">Carpellate<\/p>\n<\/div>\n<\/div>\n<p>What term describes an incomplete flower lacking a gynoecium?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"2\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q261987\">Show Answer<\/span><\/p>\n<div id=\"q261987\" class=\"hidden-answer\" style=\"display: none\">Staminate<\/div>\n<\/div>\n<\/div>\n<p>If both male and female flowers are borne on the same plant, the species is called monoecious (meaning \u201cone home\u201d): examples are corn and pea. Species with male and female flowers borne on separate plants are termed dioecious, or \u201ctwo homes,\u201d examples of which are <em>C. papaya<\/em> and <em>Cannabis<\/em>. The ovary, which may contain one or multiple ovules, may be placed above other flower parts, which is referred to as superior; or, it may be placed below the other flower parts, referred to as inferior (Figure 3).<\/p>\n<div id=\"attachment_2119\" style=\"width: 1034px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2119\" class=\"size-large wp-image-2119\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18194840\/Figure_32_01_04-1024x313.jpg\" alt=\"Part A shows a lily, which has an ovary above the petals. The ovary sits above the teardrop-shaped petals. Part B shows several fuchsia flowers hanging down from a stem. The ovary is below the edge of the petals.\" width=\"1024\" height=\"313\" \/><\/p>\n<p id=\"caption-attachment-2119\" class=\"wp-caption-text\">Figure 3.\u00a0The (a) lily is a superior flower, which has the ovary above the other flower parts. (b) Fuchsia is an inferior flower, which has the ovary beneath other flower parts. (credit a photo: modification of work by Benjamin Zwittnig; credit b photo: modification of work by &#8220;Koshy Koshy&#8221;\/Flickr)<\/p>\n<\/div>\n<p><iframe loading=\"lazy\" src=\"https:\/\/lumenlearning.h5p.com\/content\/1291236404452658868\/embed\" width=\"1088\" height=\"637\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><script src=\"https:\/\/lumenlearning.h5p.com\/js\/h5p-resizer.js\" charset=\"UTF-8\"><\/script><\/p>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_8da14a10-9030-46b9-8968-94f3f4fe4115\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/8da14a10-9030-46b9-8968-94f3f4fe4115?iframe_resize_id=assessment_practice_id_8da14a10-9030-46b9-8968-94f3f4fe4115\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-598\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology. <strong>Provided by<\/strong>: OpenStax CNX. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":6,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology\",\"author\":\"\",\"organization\":\"OpenStax CNX\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\"}]","CANDELA_OUTCOMES_GUID":"47276730-fca9-4e02-aa99-07a0117ec76f, 9a25c3f1-4033-4b33-aa64-6602c052abcb","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-598","chapter","type-chapter","status-publish","hentry"],"part":589,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters\/598","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":6,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters\/598\/revisions"}],"predecessor-version":[{"id":3000,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters\/598\/revisions\/3000"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/parts\/589"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapters\/598\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/media?parent=598"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/pressbooks\/v2\/chapter-type?post=598"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/contributor?post=598"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/wp-json\/wp\/v2\/license?post=598"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}