Immersed aquatics, branching and leafy. [Naiadaceæ], [557]

Reed-like or Flag-like marsh herbs, with linear and sessile nerved leaves; flowers in spikes or heads.

Flowers monœcious, and quite destitute of floral envelopes. [Typhaceæ], [547]

Flowers perfect, on a lateral spadix; sepals 6. [Acorus], in [Araceæ], [550]

Terrestrial or marsh plants; leaves mostly with a distinct netted-veined blade, petioled. [Araceæ], [548]

B. Petaloideous Division. Flowers not collected on a spadix, furnished with floral envelopes (perianth) answering to calyx or to both calyx and corolla, either herbaceous or colored and petal-like (wholly glumaceous in Juncaceæ).

1. Perianth adherent to the whole surface of the ovary.

Flowers diœcious (or rarely perfect), regular.

Aquatics; ovules and seeds several or numerous. [Hydrocharidaceæ], [495]

Twiners; ovules and seeds one or two in each cell. [Dioscoreaceæ], [517]