326 WELWITSCHII ITER ANGOLENSE. 
upwards, with the flowers in a dense, short spike. Fruit on our speci- 
mens (scarcely ripe) small and semicircular in form, with a greenish 
rib-like keel, not prominent when fresh, but distinctly visible when 
half dried: the younger fruit ovate, with a slight prominence on the 
back. ; 
P. nitens appears to hold a place between P. heterophyllus, Schreb., 
and P. prelongus, Wulffen. It may, however, be distinguished from 
the former by its broader lower leaves, semiamplexicaul at the base, 
channelled and reflexed, as also by its shorter peduncle, denser and 
shorter inflorescence. Besides in our plant no floating coriaceous 
leaves have been seen, either in July or September. P. prelongus has 
larger leaves, much broader at the base and hooded at the point, the 
upper not lengthening into a petiole at the base. 
Our plant was discovered in considerable quantity growing in a 
large lake, a short distance from the sea, at Castle Gregory, near Bran- 
don Mountain, county of Kerry. In the beginning of last July it was 
scarcely in flower, and in the third week in September more specimens 
were obtained from the same locality, with the fruit still immature, 
though falling off. It grew thinly scattered through the lake, having 
several stems, varying from 12 to 16 inches long, rising from the creep- 
ing root. 
ExrnawATION or Prate XXII, representing Potamogeton nitens, Weber, 
from specimens collected at Castle Gregory.—Fig. 1, an entire flower ; 2, the ova- 
ries, very young :—all magnified. 
WELWITSCHII ITER ANGOLENSE. 
[Under this title will be published, by various botanists of England, 
Germany, and Switzerland, a series of papers on the Vegetation of 
Western Tropical Africa, founded upon the valuable collections which 
that indefatigable explorer Dr. F. Welwitsch made in Angola, Ben- 
guela, and islands adjacent, when, aided by liberal grants from the Por- 
tuguese Government, he travelled through those countries. Few, or 
rather say no recent journeys have yielded a finer harvest of new genera 
and species than the explorations which Dr. Welwitsch, with so much 
credit to himself and the Government which so liberally supported 
him, conducted in these rich Portuguese possessions. They afford a 
