Aquatic or marsh herbs with a creeping root-stock and simple stems. Leaves in two ranks, linear. Inflorescences spadix-like, cylindrical, superposed, interrupted by bracts, the lower female, the upper male. Flowers unisexual, without a perianth, but usually surrounded by hairs. Stamens 2-7; connective thickened; anthers opening lengthwise by two slits. Ovary 1-celled. Ovule 1, pendulous, inverted. Style and stigma simple. Fruit tardily dehiscent. Seed with abundant albumen and a long, axile embryo. Genus 1, species 4. They are used as ornamental plants and in medicine, and yield potash and also materials for plaiting and stuffing and for the manufacture of paper and felt. The root-stock and the pollen are edible. “Reedmace.” =Typha= Tourn. [Illustration: PANDANACEAE. _FLOW. PL. AFR._ _Pl. 3._ J. Fleischmann del Pandanus Candelabrum Beauv. _A_ Whole plant. _B_ Male inflorescence. _C_ Leaf. _D_ Female inflorescences. _E_ Male flower. _A_ and _D_ (from Palisot-Beauvois Flore d’Oware et de Benin.)] [Illustration: POTAMOGETONACEAE. _FLOW. PL. AFR._ _Pl. 4._ J. Fleischmann del Potamogeton javanicus Hassk. _A_ Flowering branch. _B_ Fruiting branch. _C_ Flower. _D_ Ovary cut lengthwise. _E_ Fruit cut lengthwise.] FAMILY 6. PANDANACEAE Shrubs or trees, usually with aerial roots. Leaves in three ranks, sword-shaped, usually spiny. Flowers dioecious, without bracts, arranged in solitary or panicled, spike-or head-like spadices, which are inserted in the axil of spathe-like bracts. Perianth none. Ovaries connate, 1-celled. Ovule 1, descending, inverted. Stigma 1, sessile. Fruits drupe-like, congested into a globose or ovoid head. Seed with abundant albumen. (Plate 3.) Genus 1, species 65. Tropics. They yield timber, fibres, flowers used in perfumery, edible fruits, and medicinal drugs. “Screw-pine.” =Pandanus= L. FAMILY 7. SPARGANIACEAE Aquatic or marsh herbs with a creeping root-stock. Leaves in two ranks, linear. Flowers unisexual, in globular heads, the lower of which are female. Perianth of membranous scales. Stamens 3 or more. Ovary superior, 1-2-celled. Ovule 1 in each cell, pendulous, inverted. Style simple, stigmas 1-2. Fruits drupe-like. Seed with a mealy albumen and a large, axile embryo. (Under _TYPHACEAE_.) Genus 1, species 2. North-west Africa. “Bur-reed.” =Sparganium= L. ORDER HELOBIAE SUBORDER POTAMOGETONINEAE FAMILY 8. POTAMOGETONACEAE Aquatic herbs. Leaves with axillary scales. Flowers solitary or spicate, regular, with 1-4-merous whorls. Perianth simple and little developed or wanting. Stamens 1-4. Anthers sessile, opening outwards or laterally. Carpel 1, with a 1-celled ovary, or several distinct or almost distinct carpels. Ovules solitary in each carpel, very rarely 2, pendulous or laterally fixed Fruit indehiscent. Seed exalbuminous. Embryo with a strongly developed radicle.--Genera 8, species 35. (Including _ZOSTERACEAE_, under _NAIADACEAE_.) (Plate 4.)