Ilifdrostachijs.'] ex. podostemace^ (baker and weight). 129 



8. HYDROSTACHYS, Thouars; Benth. et Hook. f. Gen. PI. iii. 115 



Flowers dioecious. Perianth none. Male : Stamen solitary ; fila- 

 ment very short; anther oblong, :i-celled. Female : Ovary oblong, 1-celled; 

 placentas 2, parietal. Styles 2, long, liliform, connate in the lower half. 

 Capsule oblong, seated in the hollow of a concave accrescent bract, the 

 apex of which is often reflexed, 2-valved. Seeds many to each placenta. — 

 Stem short, tuberous. Leaves large, pinnately branched, usually bear- 

 ing protuberances on the petiole and rhachis. Spikes simple, tufted, 

 peduncled, much resembling the fruiting spikes of P/«?i^ft^o major, Linn., 

 each flower seated in the axil of a persistent bract. 



Species about 15, chiefly in the Mascarene Islands, one in South Africa. 

 Ultimate branches of the rhachis at least 3 lin. long, 



filiform. Leaf-segments setaceous . . . . 1. H. triaxialis. 



Ultimate branches of the rhachis rarely 3 lin. long. 



Protuberances on rhachis narrowly linear . . 2. H. angustisecta. 



Protuberances on rhachis lanceolate or palmately or 



pinnately lacerate Z. H. polymorpha. 



1. H. triaxialis, EikjI. <€• Gilg in Baum, Kicnene-Samh. Exped, 

 241. A submerged herb. Loaves about 14 in. long, 3 in. wide ; rhachis 

 tripinnate, the primary divisions alternate, the secondary subopposite, 

 all bearing subulate or elliptic protuberances, ultimate divisions bearing 

 5-8 pairs of setaceous segments J-1 lin. long formed of 2-3 chains of 

 cells ; petiole 1-2| in. long. Female spikes in fascicles of 6-10 ; peduncle 

 2-5 in. long, verrucose with black protuberances ; flowering part 2-3 in. 

 long ; bracts obovate, concave, transversely rugose in the upper part, 

 1 lin. wide. Fruit obovoid, sessile, shorter than the bract, smooth. 

 Flowers and male plant unknown. 



Ziower Guinea. Angola : in the Kubango River, above Massaca, 3900 ft. 

 on boulders iu running water, Baiim^ 263 ! 

 Native name " waterkom." 



2. H. angustisecta, Kngl. Jahrb. xxviii. 391. Rhizome tuberous. 

 Leaves multipinnate, about 1 ft. long, 2-2-| in. wide; rhachis with short 

 conical protuberances below, longer and narrowly linear ones above, 

 ultimate divisions bearing lanceolate segments J lin. long ; petiole 4 in. 

 long, 2-3 lin. in diam. Female spike 7 in. long; peduncle 8 in. long; 

 bracts 2 lin. long, 1 lin. wide, oblong, concave. Capsule oblong-ovoid, 

 slightly shorter than the bract. 



Mozamb. Blst. German East Africa : Uhebe ; on stones beneath a waterfall 

 on the Lolio Kiver, 1900 ft., Goetze, 433 ! 



Either this is a polymorphic species or Goetze's specimen at Kcw consists of 

 two species. The smaller has leaves 4 by 1^ in., with their ultimate segments very 

 narrowly linear and compressed ; the petioles, however, so strongly resemble those 

 of the larger plant as to favour tlie opinion that the species is variable. The 

 bracts when old lose their parenchyma, and then appear palmately divided. 



