EvANs: TAXILEJEUNEA PTEROGONIA 129 
size, cordate-oval in form, subpeltate (in allusion to the strongly 
arched line of attachment), and more deeply emarginate than the 
leaves, the sinus being narrow and the laciniae acute. 
This original description was drawn from sterile material 
collected on the island of St. Vincent, the name of the collector not 
being mentioned. Although the type has not been examined by 
the writer, a specimen in the Mitten Herbarium, which ap- 
parently represents a co-type, has been carefully studied. This 
specimen was collected on St. Vincent by L. Guilding and came 
originally from the Hooker Herbarium. It agrees in all essential 
respects with the original description, except that the leaves are 
acute or apiculate rather than ‘‘acuminate,” indicating that the 
latter term was not well chosen. It agrees also with the other 
specimens listed above, so far as this can be established in the 
absence of female branches and perianths. 
Unfortunately most of the important differential characters 
of the species, as here delimited, are based on these very parts, and 
the vegetative characters of T. debilis are largely duplicated in 
T. pterogonia, T. jamaicensis and (to a less extent) T. densiflora. 
In other words all four species show auricles at the base of the 
leaves and underleaves; acute for apiculate leaf-lobes, crenulate 
throughout and often sparingly dentate in the apical portion; and 
a short apical sinus on the underleaves with more or less sharp- 
pointed divisions. Both T. pterogonia and T. jamaicensis, 
moreover, show a cell-structure which is essentially like that of 
T. debilis, the trigones, intermediate thickenings and superficial 
verruculae being much the same. Under the circumstances it 
might at first seem justifiable to give up the name T. debilis 
altogether, regarding the sterile type as indistinguishable from 
the allied species. When the underleaves are carefully compared, 
however, the apical sinus of T. debilis is seen to be frequently 
rounded or lunulate, whereas this condition is rarely found in 
T. pterogonia, T. jamaicensis or T. densiflora. On the basis of 
this vague and not too constant difference the validity of T. debilis 
may still be maintained and the determination of sterile material 
may be attempted. 
In the speicimens here referred to T. debilis underleaves with 
rounded or lunulate sinuses are associated with five-keeled peri- 
