{"id":2813,"date":"2022-09-26T03:31:28","date_gmt":"2022-09-26T03:31:28","guid":{"rendered":"https:\/\/natureclearly.com\/?p=2813"},"modified":"2022-10-03T01:19:15","modified_gmt":"2022-10-03T01:19:15","slug":"leaf-morphology","status":"publish","type":"post","link":"https:\/\/natureclearly.com\/cs\/leaf-morphology\/","title":{"rendered":"Leaf morphology"},"content":{"rendered":"
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Plant leaves take on a wide variety of shapes, forms and colors, and some plants are even missing leaves completely (for example, saguaro cactus)!\u00a0<\/span><\/p>

Why learn leaf morphology?<\/b><\/p>

Although there\u2019s huge variation among different species, learning some basic leaf morphology is an important starting point for building further knowledge about plants. All of the terms are also important for when you use plant identification keys to find out a species of plant.<\/span><\/p>

Let\u2019s get started!<\/b><\/p>

We start from the point where a leaf comes off the stem. A leaf attaches to the stem at a region called<\/span> the <\/span>node<\/b>. The section between nodes (the bare stem between leaves) is called an <\/span>internode<\/b>. You might\u2019ve heard of nodes in connection with plant propagation, where it is usually recommended to \u201ccut the stem just below the node\u201d to root the cutting successfully.\u00a0<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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A leaf can be attached to the stem either directly or by a stalk. This \u201cleaf stalk\u201d is called a <\/span>petiole<\/b>, and it connects the leaf blade to the plant stem. Petioles are useful for positioning the leaves on a plant in an arrangement where they don\u2019t shade each other too much and all of them get maximum light exposure (this is important for photosynthesis\u2014a process in which plants create food for themselves).<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Petioles also vary in appearance: they can be slender, flattened, or thick and fleshy like in rhubarb. Yes, those rhubarb \u201cstalks\u201d we use for cooking and baking are actually petioles!<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Red, fleshy petioles of rhubarb<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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However, some leaves don\u2019t have petioles and the leaf blade attaches to or \u201chugs\u201d the stem directly. We call these \u201cpetiole-less\u201d leaves <\/span>sessile leaves<\/b>.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Continuing up the leaf, we arrive at the \u201cmain\u201d part\u2014the <\/span>leaf blade<\/b>, or <\/span>lamina<\/b>. This is the place in the plant where most of the photosynthesis happens, and for that purpose it is usually thin and flat. If you want to learn more about the purpose of leaves, check out our video \u201cWhy do plants (not) have leaves?\u201d<\/a> In this article, we’ll stay focused on leaf morphology.<\/span><\/p>

The size, shape, texture, color and overall look of the leaf blade play a key role in species identification. A leaf blade can be either <\/span>simple<\/b> (that\u2019s when it comes in one piece) or <\/span>compound<\/b> (that\u2019s when a leaf blade consists of multiple leaflets). Recognizing simple and compound leaves is not always straightforward and it deserves a separate article, so keep an eye out for it in the near future!<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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The \u201cbottom of the leaf\u201d is called the <\/span>leaf base <\/b>and at the tip of the leaf we have a <\/span>leaf apex<\/b>.<\/span>  <\/b><\/p>

The <\/span>leaf margin<\/b> is also an important feature and it can be smooth, entire, lobed, spiny, wavy, etc.<\/span><\/p>


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The leaf blade has an upper surface, the <\/span>adaxial <\/b>side (\u201cad\u201d meaning <\/span>towards<\/span><\/i> the stem), and a lower surface, the <\/span>abaxial <\/b>side (\u201cab\u201d meaning <\/span>away<\/span><\/i> from the stem). These terms are especially handy for when you go through a plant identification key. Most of the time, these sides look very different from each other. They often vary in color and texture. Notice that on the redwood sorrel (<\/span>Oxalis oregana<\/span><\/i>), pictured below, the underside of the leaf (abaxial side) is reddish, whereas the upper side (adaxial side) is dark green.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Across the leaf blade is a spreading network of veins. The patterns they create and the arrangement in which they are branching (or not branching) is referred to as <\/span>venation<\/b>. Veins serve as physical support for the leaf, creating a \u201cskeleton\u201d, but mainly they help circulate water and nutrients into and out of the leaf. Identifying the venation pattern might also be helpful in determining the plant species.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Leaf skeleton of Wyethia mollis. When a leaf\u2019s soft tissues, the epidermis and mesophyll, are removed (this can happen through insect damage, disease or by chemical means) you can clearly see the strong vein network of the leaf.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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To introduce a final term for our basic leaf terminology discussion, we’ll go back to the place where the leaf meets the stem. Sometimes you might find small projections called <\/span>stipules<\/b>, which usually come in pairs. They vary greatly in form. They can be leafy, like in a rose plant, they can look like thin scales or thick knobs, or they can even form glands or spines. It might be tricky to recognize them, but at least you now know where to look for them!<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Small scaly stipules of desert rose (adenium)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t
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large leafy stipules of platanus racemosa<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Quiz time!<\/b><\/p>

Now that you’ve learned all these new terms relating to leaf morphology (and hopefully watched the video for even more detailed information), here’s a little quiz to test your knowledge. You can freely download and print the PDF version below. Good luck!<\/p>

\u00a0<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Plant leaves take on a wide variety of shapes, forms and colors, and some plants are even missing leaves completely (for example, saguaro cactus)!  Why learn leaf morphology? Although there\u2019s huge variation among different species, learning some basic leaf morphology is an important starting point for building further knowledge about plants. All of the terms […]<\/p>\n","protected":false},"author":2,"featured_media":2828,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","_uag_custom_page_level_css":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[23],"tags":[],"class_list":["post-2813","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-flora"],"uagb_featured_image_src":{"full":["https:\/\/natureclearly.com\/wp-content\/uploads\/2022\/09\/lalala.jpg",1920,1080,false],"thumbnail":["https:\/\/natureclearly.com\/wp-content\/uploads\/2022\/09\/lalala-150x150.jpg",150,150,true],"medium":["https:\/\/natureclearly.com\/wp-content\/uploads\/2022\/09\/lalala-300x169.jpg",300,169,true],"medium_large":["https:\/\/natureclearly.com\/wp-content\/uploads\/2022\/09\/lalala-768x432.jpg",768,432,true],"large":["https:\/\/natureclearly.com\/wp-content\/uploads\/2022\/09\/lalala-1024x576.jpg",1024,576,true],"1536x1536":["https:\/\/natureclearly.com\/wp-content\/uploads\/2022\/09\/lalala-1536x864.jpg",1536,864,true],"2048x2048":["https:\/\/natureclearly.com\/wp-content\/uploads\/2022\/09\/lalala.jpg",1920,1080,false],"trp-custom-language-flag":["https:\/\/natureclearly.com\/wp-content\/uploads\/2022\/09\/lalala-18x10.jpg",18,10,true]},"uagb_author_info":{"display_name":"Lucie","author_link":"https:\/\/natureclearly.com\/cs\/author\/lucieindruchova\/"},"uagb_comment_info":0,"uagb_excerpt":"Plant leaves take on a wide variety of shapes, forms and colors, and some plants are even missing leaves completely (for example, saguaro cactus)!  Why learn leaf morphology? Although there\u2019s huge variation among different species, learning some basic leaf morphology is an important starting point for building further knowledge about plants. All of the terms…","_links":{"self":[{"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/posts\/2813","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/comments?post=2813"}],"version-history":[{"count":5,"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/posts\/2813\/revisions"}],"predecessor-version":[{"id":2876,"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/posts\/2813\/revisions\/2876"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/media\/2828"}],"wp:attachment":[{"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/media?parent=2813"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/categories?post=2813"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/natureclearly.com\/cs\/wp-json\/wp\/v2\/tags?post=2813"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}