Of several fibre: yielding plants the so-called aloes of the orders Amaryllidaceae and Liliaceae are common.
Comparing the flower of Gramineae with the general monocotyledonous plan as represented by Liliaceae and other families (fig.
Colchicum illustrates the corm-development which is rare in Liliaceae though common in the allied order Iridaceae; a corm is formed by swelling at the base of the axis (figs.
The tribe Ophiopogonoideae, with its tendency to an inferior ovary, suggests an affinity with the Amaryllidaceae which resemble Liliaceae in habit and in the horizontal plan of the flower, but have an inferior ovary.
The western dry areas have the old-world leguminous Astragalus and Prosopis (Mesquit), but are especially characterized by the northward extension of the new-world tropical Cactaceae, Mgmmillaria, Cereus and Opuntia, by succulent Amar llideae such as A gave (of which the so-called American aloe is a type), and by arborescent Liliaceae (Yucca).
The seven series of Monocotyledons represent a sequence beginning with the most complicated epigynous orders, such as Orchideae and Scitamineae, and passing through the petaloid hypogynous orders (series Coronarieae) of which Liliaceae is the representative to Juncaceae and the palms (series Calycinae) where the perianth Ioses its petaloid character and thence to the Aroids, screw-pines and albuminous Dicotyledons the cotyledons act as the absorbents of the reserve-food of the seed and are commonly brought above ground (epigeal), either withdrawn from the seed-coat or carrying it upon them, and then they serve as the first green organs of the plant.