Heteranthera] XII, PONTEDERIACES, 67 
2. HETERANTHERA Ruiz & Pavon; Benth. & Hook. f. 
Gen. Pl. iii. p. 838. 
1. H. sp. 
CazenGco.—A lacustrine plant with habit of Alisma or Sagittaria 
laxly rooting in watery mud, acaulescent, scapigerous, with swimming 
subpeltate leaves, petioles very long, septate. Margins of Lagoa de 
Moambege near Dalatando. Flowers almost over, June 1855. No. 3015. 
_ Perhaps a new species of the genus ; but in the absence of flowers it 
is impossible to say. The leaves are more or less orbicular with a 
cordate base. 
3. MONOCHORIA Presl; Benth. & Hook. f. Gen. Pl. iii. 
p. 839. 
1. M. vaginalis Pres], Reliq. Henk. i. p. 128 (1827); Solms- 
Laub. in DC. Mon. Phan. iv. p. 524 (1883). 
Punco ANponGo.—A perennial herb growing in marshes, with 
membranous, green, swimming leaves. Ponds near Banza de Quitage. 
Without fl. March 1857. No. 3013. 
Indistinguishable from the type, which has hitherto not been recorded 
from Africa. 
XU XYRIDEX. 
1. XYRIS L.; Benth. & Hook. f. Gen. Pl. iii. p. 842. 
1. X. Umbilonis Nilss. in K. Svensk. Vet. Akad. Handb. xxiv. 
No. 14, p. 30 (1892); Durand & Schinz, Consp. FI. Afr. v. p. 421. 
Punco ANDONGO.—A perennial widely czspitose herb, 2 to 23 ft, 
high ; stem and leaves glaucous, rigidulous ; flower-spikes ovoid- 
cylindrical, dark-brown, flowers yellow. Damp meadows by the 
banks of the Cuanza near Bumba. In fl. and fr. March 1857. No. 2460. 
HviLia.—Spongy marshes at the foot of Serra de Oiahoia, Humpata. 
Towards the end of April 1860. No. 2475. 
The Angolan specimens differ from the South African in their 
slightly narrower sepals and the greater extent of the non-polished 
area in the upper half of the bract, but the differences are insufficient 
for specific distinction. 
2. X. rigidescens Welw. ms. in herb. 
Glabrous, leaves rigid, flattened, linear, tapering rapidly above 
to the shortly pungent apex, sheath very broad and reddish-brown 
below, narrowing upwards ; peduncles far exceeding the leaves, com- 
pressed, sheath broadly linear, reddish-brown to the middle, leafless, 
ending abruptly in a sharp stiff apiculus ; spikes subglobose ; lower 
bracts very tough and leathery, orbicular to very broadly oblong, 
concave, becoming keeled below the strongly apiculate apex, dirty 
brown with thinner straw-coloured entire edges, upper half with a 
circular submuriculate area ; becoming broadly ovate, less rigid 
and less deeply coloured above; shorter than the lateral sepals 
which are suboblong when opened out, with sides of a pale 
straw-colour passing into the dark brown keel which is shortly 
ciliate up to the base of the strong apiculus ; flowers withered, 
corolla-segments apparently oblong, staminodes 2-armed densely 
pilose, shorter than the stamens, anthers broadly linear; unripe 
fruit compressed, broadly oval. 
