Monocots
Monocots
Monocots make up one of the largest groups of angiosperms, or flowering plants, comprising a total of twenty-five percent of all angiosperms (Fay, 2013). The term monocot, stems from most membering plants having one seed leaf, known as a cotyledon. There are nearly 60,000 different species of monocots and together they form a monophyletic group (Bremer, 2000). Famous monocot families include Orchidaceae (orchids), the largest known plant family, Iridaceae (irises), Arecaceae (palms) and more (Tang et al., 2017). Monocots are of great economic and cultural importance around the world (Tang et al., 2017).
Physical Structure
The identifying feature of a monocot is a trimerious-pentacyclic flower design. This design consists of six tepals in two whorls, six stamens in two whorls, and three carpels. These features are virtually absent from earlier angiosperms (Remizowa, Sokoloff, & Rudall, 2010). Floral parts in monocots typically occur in threes (Robinson, 2016). Monocots are also known to have leaves with parallel venation, the veins are arranged parallel to one another and do not join other veins. Monocotyledons differ from the other main group of angiosperms, eudicots, in their vascular structure. Monocots have primary vascular bundles containing both phloem and xylem in a scattered arrangement, known as an atactostele. There is no differentiation between cortical and stellar regions in monocots. This contrasts eudicots, which have a ring like vascular bundle shape with a distinct phloem and xylem, differentiated by the cortex and stele (Zimmermann and Tomlinson, 1972). Root systems in monocots are characterized by a radical which aborts at an early stage. Since the first root that emerges dies, a central taproot forms and roots grows adventitiously (Chase, 2004). Adventitious roots sprout from shoot tissues near the base of the monocot. Monocots also lack a cambium, which allows for growth in diameter with height (Chase, 2004). Due to the lack of cambium, there is a limit on how tall shoots can grow and many monocots tend to be herbaceous. However, some monocots are able to reach great height, length and mass such as agaves, palms, and bamboos.
