68 A FLORA OF MANILA 



2. RUPPIA Linnaeus 



Slender, branched, submerged plants growing in brackish water. Leaves 

 very slender, elongated, filiform, entire, the bases with broad sheaths. 

 Flowers small, perfect, 2 to 6 together within the leaf -sheath on a short 

 peduncle which elongates after flowering. Perianth none. Anthers 2, 

 sessile, opposite. Carpels 4 or more and sessile, 1-ovuled, in fruit long- 

 stipitate, ovoid, beaked. (In honor of H. B. Rupp, a German botanist,) 



A single variable species in brackish water in most warm and tropical 

 regions. 

 1. R. maritima L. var. rostrata Agardh. Digman-palay (Tag.). 



Stems very slender, branched, up to 50 cin in length. Leaves thin, 

 linear, entire, flat, 5 to 7 cm long, less than 1 mm wide, the sheaths 

 auriculate. Flowers very small. Peduncles elongated after flowering, 

 straight, slender, 1 cm long or more. Achenes obliquely ovoid, beaked, 

 about 2.5 mm long, and slenderly pedicelled, 4 or 5 or more subumbellately 

 arranged on each peduncle. 



In brackish water, fish-ponds at Malabon, fl. Dec.-Feb., and probably in 

 other months; of very local occurrence in the Philippines. In mosj warm 

 and tropical countries. 



11. NAJADACEAE (Najas Family) 



Slender, branched, submerged plants, the leaves numerous, small, linear, 

 toothed, sheathing at the base, in pairs, sessile. Flowers . small, axillary, 

 monoecious, rarely dioecious. Male flowers naked or included in a small, 

 spathe, the perianth 2-lobed, adnate to the solitary anther. Female flowers 

 naked, rarely included in a spathe, the perianth none, the ovary 1-celled, 

 1-ovuled. Fruit small, included in the leaf-sheaths, the pericarp thin, 

 adherent to the seed. 



A single genus. 



1. NAJAS Linnaeus 



Characters of the Family. (From the Greek "water nymph.") 

 Species 32, with many varieties, in all parts of the world, 3 in the 

 Philippines. 



1. N. graminea Del. 



A slender branched plant 20 to 60 cm in length. Leaves linear, numerous, 

 opposite, 1 to 2 cm long, finely toothed, inflated and with toothed auricles at 

 the base. Flowers small, naked, fascicled, monoecious; anthers 4-celled. 

 Fruit oblong-ellipsoid, about 2 mm long. 



In stagnant fresh water, fl. March-May and probably in other months ; 

 widely distributed in the Philippines. Northern Africa to Japan south to 

 Australia. 



12. HYDROCHARITACEAE (Eel Grass Family) 



Aquatic, fresh or salt-water herbs, with simple, undivided leaves. 

 Flowers monoecious or dioecious, enclosed in an entire or 2-leaved spathe. 

 Sepals 3, green or petaloid. Petals 3 or none. Stamens 3 to 15; anthers 

 erect. Ovary inferior, the placentas parietal or projecting; styles or style- 

 arms 3 to 12. Fruit rarely dehiscent, membranaceous or fleshy, few- to 

 many-seeded. 



