482 DR. OTTO STAPF ON 
(Since this paper was read, a quantity of Halimeda material 
has come into my hands, and I have been allowed access to some 
valuable authentic specimens of Kuetzing, Hauck, and others. 
An examination of these plants shows clearly the necessity for 2 
revision of the genus and a certain modification in the number of 
the species—a task I hope to carry out later.—19¢h Sept., 1900.] 
EXPLANATION OF PLATE 18. 
Fig. 1. Halimeda laxa, n. sp. 3 nat. size. 
2, » » Peripheral cells, decalcified surface view. x 140. 
3. » „ Ditto, decalcified side view. 375. 
4. H. cuneata, Kuetz., var. nov. elongata. 7 nat. size. 
5. » Peripheral cells, decalcified surface view. X 140. 
DICELLANDRA, Hook. fi, and PHEONEURON, Gilg (Melastomacez). 
By Dr. Orro Srap¥, A.L.S. 
[Read 7th June, 1900.] 
(Prate 19.) 
1. 
Tur Melastomaceous genus Dicellandra was described by Sir 
Joseph Hooker in Benth. & Hook. f. Gen. Plant. i. 757, from 
specimens collected by Barter on the Nun River and by G. Mann 
in the island of Fernando Po, and the only species then known 
was named D. Barteri, Hook. f. The same author added a 
second species to the genus in Oliver's Flora of Trop. Afr. ii. 
459, from specimens collected by Afzelius in Sierra Leone. This 
was called D. setosa, Hook. f. Since then several Melastomacez 
have been received at Kew from West and Central Africa, which 
superficially very closely resemble the original D. Barteri; 
indeed, so much so, that Cogniaux enumerates them under this 
species in his great monograph of Melastomaces, p. 546. Among 
them is a specimen gathered by Schweinfurth in Monbuttuland 
(no, 3166). When Gilg worked out the Melastomace: for the 
* Nachtrüge" of Engler and Prantl’s ‘Natürliche Pflanzenfamilien' 
and for Engler's ‘ Monographien Afrikanischer Pflanzenfamilien,’ 
his suspieion was aroused concerning the specifie, and even the 
generic, identity of Sehweinfurth's plant with the original Dicel- 
landra Barteri, and he asked me to compare both. In my reply 
(see Gilg in Engl. Monogr. Afr. Pflanzenfam. ete. ii. 85) I told 
him that, of the specimens referred to D. Bartert by Cogniaux, 
