1623. The roots are mostly tubers or bulbs, containing a superior kind of mucilage, or aromatic principles. The shaft is not hollow but, though herbaceous, filled up; the leaves are elevated upon the stalk. One division of these plants has irregular corollæ with stunted stamina and capsules, the latter containing mostly dust-like seeds, as in the Orchideæ and aromatic plants. 1624. The other division has regular 2 × 3ary corollæ, with, perfect glume-capsules and middling-sized seeds, as the Irideæ and Liliaceæ proper. 1625. The first order, _Parenchymatose lilies_. The corollæ are irregular, bilabiate, and stand upon the calyx and a membranous sexlocular capsule with very small seeds; are divided according to the pollen--e. g. _pulverulent Orchideæ_. 1626. The second order, _Sheath-lilies_. Characters similar to those of the preceding order, but the pollen is agglomerated into waxy granules--_granular orchideæ_. 1627. The third order, _Stem-lilies_. The corollæ are likewise bilabiate and situated above the calyx, but the ovarium contains few seeds, and the capsule is mostly nut-like--_aromatic plants_, such as the _Scitamineæ_ and _Musaceæ_. 1628. The fourth order _Floral-lilies_, have regular blossoms, separated into calyx and corolla, placed _above_ the capsule, and mostly furnished with three stamina. Here belong the _Hypoxideæ_, _Hæmodoraceæ_ and _Irideæ_. 1629. The fifth order, _Fruit-lilies_. The leaves have not yet completely separated from each other, but still form bulbs; the corollæ are regular, have six stamina, and are placed _beneath_ the capsule, as in the _true lilies_. To this order belong the _Colchicaceæ_, _Aloinæ_ and _Liliaceæ_. Their bulbs contain mostly acrid matters. They divide into sixteen families. (Vid. Tab. B.) _CLASS VI._ _Wood-plants--Palmaceæ._ _Plants with woody shaft and with fruits, mostly enclosed in spadices._ 1630. The desiccation of the cells and fibres is promoted by the increased process of oxydation. Where therefore the tracheæ attain the preponderance, there the conversion into wood originates. 1631. The stalks of these plants are not hollow, but have a dense interior, because the fasciculi of tracheæ lie within the liber, and there increase. 1632. The main bulk of the stalk will consist of tracheæ. 1633. As the tracheæ are longitudinal organs, and the other tissues also extend lengthways, so does the stalk or stem in these plants predominate over the other parts. 1634. In this class the most perfect leaves as regards their present stage are developed; for they are only expansions of the tracheæ, which are here present in superabundance. As regards the form also, these leaves must rank higher than those of the preceding class; the spathe is shorter, the leaf itself usually broad, many-ribbed, and frequently pinnate. The leaves are also perfect as to position, being no longer mere radical leaves, but situated upon the stalk, even on its apical extremity.