Hemi-hydrophytes (swamp plants, marsh plants, &c.).Plants riose vegetative organs are partly submerged and partly aerial; lucheria terrestris, Philonotis fontana, Sca pan-ia undulata, Maria spp., Salvinia ivatans, Azolla spp., Equisetum limosum, Typha rgustifolia, Phragmites communis, Scirpus lacustris, Nymphaea tea, Oenanthe fistulosa, Bidens cernua.
The Salviniaceae include the two genera Salvinia (fig.
Azolla has roots depending from the lower surface of the stem into the water, while these organs are completely wanting in Salvinia, their place being taken functionally by highly divided leaves borne on the ventral surface of the stem.
In Salvinia (fig.
- Salvinia natans.