Editing Monocotyledon (section)

===Vascular system===
[[File:Royal Palm Trunk.jpg|thumb|''[[Roystonea regia]]'' palm ([[Arecales]]) stems showing anomalous secondary growth in monocots, with characteristic fibrous roots]]

Monocots have a distinctive arrangement of vascular tissue known as an [[Stele (biology)|atactostele]] in which the vascular tissue is scattered rather than arranged in concentric rings. [[Collenchyma]] is absent in monocot stems, roots and leaves. Many monocots are [[herbaceous]] and do not have the ability to increase the width of a stem ([[secondary growth]]) via the same kind of [[vascular cambium]] found in non-monocot [[woody plant]]s.{{sfn|Chase|2004}} However, some monocots do have secondary growth; because this does not arise from a single vascular cambium producing [[xylem]] inwards and phloem outwards, it is termed "anomalous secondary growth".{{sfn|Donoghue|2005}}  Examples of large monocots which either exhibit secondary growth, or can reach large sizes without it, are palms ([[Arecaceae]]), screwpines ([[Pandanaceae]]), bananas ([[Musaceae]]), ''[[Yucca]]'', ''[[Aloe]]'', ''[[Dracaena (plant)|Dracaena]]'', and ''[[Cordyline]]''.{{sfn|Chase|2004}}