Submerged plant; stems slender, branched. Submerged leaves narrow-lin., 2-3 in. long; floating leaves lanceolate, ½ in. or more, long petioled; lower stip. connate, upper free. Ped. axillary; spikes ¼-¾ in. long. Fr. 2-keeled. White Nile Prov. (Jebelein, Goz Abu Gum’a); Bahr El Jebel (Sudd); Bahr El Ghazal Prov. (Mouth of Bahr El Arab; Niamniam-land: River Rei, Gumango Hill). =P. crispus= _Linn._ Stem compressed, slender, branched. Leaves all one shape, semi- amplexicaul, obl. or obl.-strap-shaped, undulate, serrulate; stip. small. Ped. in forks of the stem, stoutish; spike large lax-flowered. Fr. obliquely ovoid with long curved beak. Nubia; Khartoum Prov. (in White Nile); Blue Nile Prov. (Sennar); Kordofan Prov. =P. pusillus= _Linn._ Stem slender, branched. Leaves all similar, semi-amplexicaul, narrow- lin., acumin. or acute; stip. small, acute. Ped. slender; spike few- flowered, ¼-½ in. long. Fr. semi-oval or obovoid, bluntly 3-keeled. Darfur Prov. (J. Marra: below Niurnya 5,500 ft.). =P. lucens= _Linn._ Stem stout, branched. Leaves all submerged, the lower lin.-lanc. to lanc., the lowest sessile, petioled above, the pet. gradually lengthening to ab. 1 in.; upper leaves lanc. to ovate; stip. long, beaked or winged. Ped. 2-9 in. long, stout; spikes ab. 2 in. long, dense. Fr. slightly acumin., slightly convex on ventral and semicircular on dorsal margin. Bahr El Jebel (2° N.L.). =NAIADACEÆ.= 736 =Naias graminea= _Del._ Submerged plant; stems up to 2 ft. long, slender, rooting at lower nodes. Leaves sometimes in clusters at the nodes, linear, closely serrate and with an auricled serrate sheath. Infl. monœcious, axillary, male and fem. side by side or fem. only, all without spathes. Male fl. solitary; per. ending above anther in ear-like lobes; anther 1, subsessile; fem. fl. 1-4, consisting of a single ovary, sessile, with 2 stigmas. Fr. lin.-obl. White Nile Prov. (Um Kinein near J. Arashkol); Bahr El Ghazal Prov. (Jur: Kutshuk Ali’s Zariba). =N. Schweinfurthii= _Magnus._ Small water plant with spreading branches. Leaves thin, slender, with ab. 12 marginal teeth, ending in a brown spine; sheaths with short, obtuse auricles. Infl. monœcious; male spathe oblong; anther 1-celled. Fem. spathe oval-oblong, produced into a neck round the long style. Bahr El Ghazal Prov. (Jur: Jur Ghattas). =N. horrida= _A. Br._ Water plant; stems long, short branched; inter-nodes short. Leaves falcate with spinulose teeth; sheaths rounded, toothed; male flower only with spathe; anther 4-celled. Fung Prov. (Fazoghli); White Nile Prov. (Goz Abu Gum’a); Bahr El Ghazal Prov. (mouth of Jur River, etc.). 737 =Cymodocea rotundata= _Aschers._ & _Schweinfth._