m 
WILLI8 : PODOSTEMACEÆ 
shoots distichous, chiefly on the floating thalli, usually about 5 mm. 
apart ; the lower or f or rarely more ultimately floriferous, Flori- 
ferous part of thallus woody, and the rest of the thallus, including 
the marginal parts of the floriferous portion, usually deciduous, at least 
on exposure to the air. Floral shoots in bud usually linear to oblong, 
widening upwards, not crowded together, the axis elongated above the 
surface of the thallus, with 2-5 (usually 4) distichous scales. Scales 
imbricate, often connate at base, most often with pointed tips after the 
fall of the leafy ends, but frequently more or less cowl-shaped. Spathe 
at first included, soon emergent, 2-5 mm. long when open. Pedicel 
about 4-5 mm. lengthening to about 5-9 mm. in ripe fruit. Stamens 
2, equalling ovary with stigmas, staminodes shorter. Ovary smooth. 
Stigmas 2, sessile, shorter than ovary, stout, subulate, marcescent or 
deciduous. Capsule 1-24 mm. oblong- elliptical, 8-ribbed. Fruiting 
thallus more or less erect on rocks. 
Ceylon on rocks in rapids to 2,000 feet. Flowers January 
to March. First discovered by Gardner. Endemic. 
Mahaweli-ganga in Ambegamuwa, Gardner, Mahaweli- 
ganga near Peradeniya, Gardner ! Thwaites, C. P. 2,259 ! 
Trimen ! Mahaweli-ganga at Hakinda rapids, Willis ! 
Kelani-gangaatKitulgala, Trimen ! Bambarabotuwa-ganga, 
H. F, Macmillan ! 
A very distinct species, easily recognized by the long fila- 
mentous fioating thalli, and by the comparatively widely 
separated and narrow fioral shoots. The thallus tips are 
commonly missing in herbarium specimens. The Bambara- 
botuwa specimens have a rather smaller habit and more 
cowl-like bracts, but more material is required to decide 
whether they are specifically or even varietally distinct. 
Sometimes mixed in herbaria with D. stylosa laciniata. 
Good figures of this species are given by Tulasne (Monogr., 
t. IX.) and Warming (1. c. II., t. X.). See also PI. XVIII., 
XIX.,. in subsequent paper. 
D1GRÆA DICHOTOMA, Tul. in Ann. Sc. Nat., 1. c., 1849, 
and in Mon. Pod., p. 119 ; Wight^ Wedd.^ Warming^ II. cc.; 
D. Wightii, Tul.^ 11. cc.; D. rigida, Tul,, WiglityW.cc,: 
D. longifolia, WightA-Q>\ Podostemon dichotomum, Wightii, 
rigidum, Gardn, in Calc. J. N. H., YIL, 1846 ; P. dichotomum, 
vars., Benth. in Hook. FI. Br. Ind., &c. 
