Photograph of a field of sugarcane. The photograph shows a field of tall green plants with long, thin leaves. Some of the plants have a feathery inflorescence at their tips.

Sugarcane morphology and anatomy

Page snapshot: Introduction to the structure of the sugarcane plant, including the morphology (form) and anatomy (internal structure) of stems and leaves. Also covers the organization of the reproductive structures.

Topics covered on this page: Introduction; Stems; Leaves; Reproductive structures; Inflorescences, spikelets, and florets; Fruits; Resources.

Credits: Funded by the National Science Foundation. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Page by Elizabeth J. Hermsen (2023).

Updates: Page last updated January 30, 2023.

Image above: A field of sugarcane (Saccharum officinarum). Photo of Forest and Kim Starr (Image number: 5416923, Invasive.org, Creative Commons Attribution 3.0 United States license, image cropped and resized).

Introduction

The purpose of this page is to introduce the basic structure of sugarcane plants (Saccharum species) with a focus on domesticated sugarcane (Saccharum officinarum) and its hybrids, as well as its close relatives robust sugarcane (Saccharum robustum) and wild sugarcane (Saccharum spontaneum). 

Photograph of bundles of sugar cane near a market stall. The photo shows multiple bundles of sugarcane standing upright, with a few bundles laying the on the ground to the left. The sugarcane stalks are purple with regularly spaced with bands. Elongated leaves are born near the tops of the sugarcane stems.

Bundles of sugarcane that have been harvested standing near a food stall. Photo by Thamizhpparithi Maari (Wikimedia Commons, Creative Commons Attribution-ShareAlike 3.0 Unported license, image cropped and resized).

Stems

Cultivated sugarcane has a single thick stalk or culm that ends in an inflorescence. The culms can be up to 19.5 feet (6 meters) tall! Unlike in many other grasses, the interior of a sugarcane stem is solid in both nodal and internodal regions. In this way, it resembles the stem of maize (Zea mays) and sorghum (Sorghum bicolor), two other domesticated plants in Tribe Andropogoneae.

Two-panel photograph figure made up of pictures showing sugarcane stems. Panel 1: A small clump of sugarcane plants with reddish stems that have narrower white bands at regular intervals. The white bands are the nodes. The upper parts of the stem bear long, thin leaves. Panel 2: A closer view of the stems.

Sugarcane plants (Saccharum officinarum) and detail of stems (culms). Note the clear nodal (light bands) and internodal (reddish regions) of the stem. Photos by Forest and Kim Starr, Starr Environmental (Image numbers 5412630 and 5412631, Invasive.org, Creative Commons Attribution 3.0 United States license, images cropped and resized).

Photograph of a pile of cut sugar cane stalks showing that the centers of the stem are solid in the internodal regions.

Sugarcane (Saccharum) culms (stems) that have been cut, showing the solid central region. Photo by ruurmo (flickr, Creative Commons Attribution 2.0 Generic license, image resized).

Leaves

Sugarcane leaves are organized like the leaves of other grasses. Each leaf consists of a sheath that wraps around the stem and an elongated blade that sticks out from the side of the stem and intercepts sunlight. The major leaf veins are parallel. The ligule is membrane-like with a fringe of hairs.

Two-panel photograph figure made up of pictures showing sugarcane leaves. Panel 1: Portion of a sugarcane stem and leaf bases. The photo shows a stem with alternately arranged leaves. Each leaf has a green sheath with tan margins clasping the stem and a green blade angled away from the stem. Panel 2: Photo showing a portion of a leaf blade arching toward the viewer. The leaf is elongated and green with a lighter midrib.

Sugarcane (Saccharum officinarum) foliage leaves. Left: Detail of leaves attached alternately (one at a time) to a stem, showing sheaths and blades. Right: A leaf blade. Photos by Forest and Kim Starr, Starr Environmental (Image numbers 5420239 and 5420237, Invasive.org, Creative Commons Attribution 3.0 United States license, images cropped and resized).

Reproductive structures

Inflorescences, spikelets, and florets

Sugarcane inflorescences are featherlike panicles. A panicle is an inflorescence with a central stem and lateral (side) branches. The lateral branches bear rames (delicate, spikelet-bearing branches that break apart when mature), and each rame has many pairs of spikelets. 

Photograph of a herbarium sheet of a sugarcane inflorescence. The inflorescence has a central stalk bearing many delicate branches with feathery hairs. The inflorescence is longer than the herbarium sheet, so in has been folded over to fit.

Inflorescence of sugarcane (Saccharum officinarum) showing feather-like structure. Herbarium sheet, specimen collected in Puerto Rico by Louisiana State University, Shirley C. Tucker Herbarium (LSU-Vascular Plants) (image via GBIF.org, Creative Commons Attribution-NonCommercial 3.0 Unported license, image cropped, resized, and labeled).

Photograph of part of a feathery inflorescence of a wild sugarcane plant. The photo shows delicate branches with feathery white hairs and brown anthers which have probably shed their pollen.

Detail of the inflorescence of wild sugarcane (Saccharum spontaneum) showing rames and feathery hairs. Photo by Judgefloro (Wikimedia Commons, Creative Commons Attribution-ShareAlike 4.0 International license, image resized).

The spikelets in sugarcane are mostly in pairs, although the spikelets at the ends of branches are in groups of three. Each spikelet pair includes one pedicellate (stalked) spikelet and one sessile (stalkless) spikelet; groups of three spikelets have one sessile and two pedicellate spikelets. Each spikelet has one fertile floret. The fertile floret is bisexual, meaning that it has both stamens (male or pollen-producing structures) and a pistil (female or ovule-producing structure). 

Photograph of part of a wild sugarcane inflorescence. The photo shows the tips of multiple delicate branches with feathery white hairs. Yellowish stamens dangle from the branches.

Anthers dangling from the spikelets of wild sugarcane (Saccharum spontaneum). Photo by Dinesh Valke (Wikimedia Commons, Creative Commons Attribution-ShareAlike 2.0 Generic license, image cropped and resized).

Fruits

Following pollination and fertilization, the fertile florets mature into fruits. Sugarcane fruits are grains or caryopses. Inflorescences of sugarcane disarticulate (break apart) when they are mature. They break in two places: The pedicellate spikelets break away from the tips of their pedicels, and the rame axes (the small branches that bear the spikelets) break apart under each of the sessile spikelets. Thus, the sessile spikelets are dispersed with two short stalks attached: the pedicel from the pedicellate spikelet and a portion of the rame axis (branch).

Photograph of three disseminules of wild sugarcane. Each of the disseminules consists of a sessile caryopsis (grain) with its surrounding bracts and two attached stalks. The shorter stalk is a pedicel from the pedicellate spikelet and the longer stalk is part of the rame axis (branch).

Disseminules (dispersal units) of wild sugarcane (Saccharum spontaneum). Each disseminule pictured here consists of a mature sessile spikelet (caryopsis and surrounding bracts) and two attached stalks (the pedicel from the pedicellate spikelet and a portion of the rame axis). Photo by Julia Scher, Federal Noxious Weeds Disseminules, USDA APHIS PPQ (Image number 5376777, Invasive.org, Creative Commons Attribution-NonCommercial 3.0 United States license, image cropped, resized, and labeled).

Photograph showing two views of a disseminule of sugarcane. The disseminule consists of a sessile caryopsis (grain) with its surrounding bracts and two attached stalks. The shorter stalk is a pedicel from the pedicellate spikelet and the longer stalk is part of the rame axis (branch).

Disseminule of sugarcane (Saccharum officinarum) with rame axis and pedicel attached to a mature sessile spikelet. Photo by Julia Scher, Federal Noxious Weeds Disseminules, USDA APHIS PPQ (Image number 5376773, Invasive.org, Creative Commons Attribution-NonCommercial 3.0 United States license, image cropped, resized, and labeled).

A sugarcane caryopsis (fruit) consists of a sugarcane embryo and endosperm surrounded by a pericarp (fruit wall). 

The sugarcane embryo, like grass embryos generally, is complex. The upper end of the embryo is covered by a coleoptile, or protective sheath. The radicle (embryonic root) at the opposite end of the embryo, is also protected by a sheath, the coleorhiza. A cotyledon (seed leaf) called a scutellum is attached to the embryo between the plumule and the radicle. The outer layer of the endosperm is the aleurone layer. 

Drawing of a longitudinal section of sugarcane caryopsis or grain. The drawing shows an oval grain with an embryo in the lower left and the remainder of the grain taken up by endosperm. The embryo includes the following labeled parts: scutellum, coleoptile, foliage leaf, shoot apex, radicle, root cap, and coleorhiza. The aleurone layer is a single layer of cells surrounding the remainder of the endosperm.

Longitudinal section of a sugarcane caryopsis showing the embryo and endosperm. Source: Modified from figure 16 in Artschwager et al. (1929) Journal of Agricultural Research 39: 1-30 (via USDA National Agricultural Library Digital Collections).

Resources

Websites

Glossary of botanical terms used in Poaceae (Flora of China online): http://flora.huh.harvard.edu/floradata/002/vol22/poaceaeglossary.htm

Poaceae (Graminae) (University of Hawai'i): http://www.botany.hawaii.edu/faculty/carr/po.htm

Scientific articles and books

Artschwager, E., E. W. Brandes, and R. C. Starrett. 1929. Development of flower and seed of some varieties of sugar cane. Journal of Agricultural Research 39: 1-30. https://handle.nal.usda.gov/10113/IND43967678

Clark, L. G., and E. A. Kellogg. In Flora of North America Editorial Committee, Flora of North America North of Mexico vol. 24. Poaceae. Accessed online at: http://floranorthamerica.org/Poaceae

Kellogg, E. A. 2015. Flowering Plants, Monocots, Poaceae. The Families and Genera of Vascular Plants 13, 416 pp. (K. Kubitzki, ed.). Springer International Publishing, Switzerland. https://doi.org/10.1007/978-3-319-15332-2_1

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