256 _CRAIB—DIDISSANDRA AND ALLIED GENERA. 
rosette which, in the young stage at least, is nearly always dense. 
In a few species.stolons are present and the flat rosette is some- 
what modified. No stem is developed above ground. Each 
plant bears several peduncles, erect or ascending, sometimes I- 
flowered but usually bearing several or many flowers, arranged 
in a more or less umbelliform manner. Bracts are wanting. 
The calyx is always divided practically to the base into five seg- 
ments. The corolla is medium-sized or small, the tube cylindrical, 
not inflated upwards, and the limb is always bilabiate with the 
posticous lip shorter than the anticous. Externally the corolla 
tube is glabrous. Internally the tube is pilose on the anterior 
side, the hairs, rather thick, being arranged in two rows which 
alternate with the lobes and which run from the top of the tube 
to about the insertion of the filaments. And again these hairs 
arise in groups from tubercled protuberances. Internally on the 
posterior side the tube is glabrous. The anther cells diverge, 
the lines of dehiscence becoming soon confluent, their course 
being at right angles to the filament. After the pollen is shed 
the anthers are drawn back nearly to the base of the corolla tube 
by the filaments coiling spirally. The inner face of the placental 
lamellae is conspicuously hairy—a character well seen in the fruit. 
The floral characters, and more especially the distribution of the 
hairs on the inside of the corolla, the structure and method of 
opening of the anthers and the retracting of the anthers by the 
spiral coiling of the filaments serve as absolute distinguishing 
marks of the genus Didissandra as understood by me. 
The remaining Chinese plants which have been referred to 
the genus Didissandra at various times it is proposed to dis- 
tribute among three new genera: Briggsia, Ancylostemon, and 
Isometrum. Characters by which the restricted Didissandra 
may be distinguished from these new genera have already 
been pointed out. 
Of the three new genera Briggsia may be easily recognised 
by the large corolla, ventricose at or just above the middle, and 
by the gradual inarching of the filaments. In the other two 
genera the corolla is medium-sized (in Ancylostemon slightly 
ventricose, in Isometrum not ventricose), and the filaments are 
straight throughout practically their whole length, the pairs of 
anthers being brought into contact by practically a right-angle 
bend just at the apex of the filament. As regards Isometrum, it 
can be recognised from Didissandra, Briggsia, and Ancylostemon 
by the spreading corolla limb, which is composed of five almost 
equallobes. In the other three genera the limb is most distinctly 
bilabiate. 
: Species in cultivation.—Of the species enumerated there are, 
_ so far as I am aware, only fivein cultivation. Isometrum Farreri 
