=A. x. hybrida= is a striking dwarf variety with vittate leaves, and smaller, more crowded deltoid-cuspidate prickles than in the type. It is also commonly known as _A. x. vittata_ and _A. perbella_.
[Illustration: FIG. 48. AGAVE YUCCÃFOLIA.]
=A. yuccæfolia= (Yucca-leaved).* _fl._ greenish yellow, 1-1/4in. to 1-1/2in. long, in a dense spike 6in. to 15in. long, about 14in. in diameter, sessile, solitary, or in pairs; scape 12ft. to 20ft. high. _l._ twenty to forty in a dense, shortly-stemmed rosette, linear, much recurved, 1-1/2ft. to 2-1/2ft. long, 3/4in. to 1in. broad at the middle; face deeply channelled, dull, rather glaucous green, with a pale band down the centre, the tip not at all pungent, the back broadly rounded, edge entire, or obscurely serrulate. Mexico, 1816. A most distinct species. See Fig. 48.
=AGERATUM= (from _a_, not, and _geras_, old; in reference to the flowers being always clear). SYN. _CÅlestina_. ORD. _Compositæ_. This genus includes several American species, for the most part half-hardy annuals and biennials; or, if the seed is not allowed to ripen, they become perennials. Involucre cup-shaped, of many imbricated linear bracts; receptacle naked. Leaves opposite. A light rich soil is most suitable. Very easily increased by cuttings or seeds; if required true, the former is the only sure method of propagation. To grow large plants for greenhouse decoration, sow the seeds in January, in heat, in sandy soil, barely covering them. As soon as the young plants are large enough, prick them off into thumb pots, and keep in heat till they grow freely, then place them into a cooler house. Transfer into larger pots as soon as the others are full of roots, until they are finally shifted into 10in. or 12in. pots. When these are full of roots, the plants should be watered with liquid manure twice a week, and they soon flower well, making fine specimens. During hot weather especially, they should be well syringed with clear water daily, to keep down red spider. The plants required for bedding (for which purpose the dwarf garden varieties are mostly used) should be raised about the same time, kept in small pots, gradually hardened off, and planted out in the middle or end of June. Cuttings of all the varieties strike readily in heat, treated like most soft-wooded plants, and, when rooted, may be managed as recommended for the seedlings.