286 
ALBAN STEWART 
Forma duncanensis Robinson 
Described as being unarmed. Leaves entire narrow lanceolate, 
acute at base and apex. Specimens from Barrington, Duncan, and 
Jervis Islands have been assigned to it.'^ 
Except for the spine-like endings of the lateral branches, the speci- 
men from Barrington Island is weakly armed, but hardly so much as is 
the specimen from Jervis Island where the spines are very weak 
indeed. The specimen from Duncan Island has very heavy spines. 
Notwithstanding the fact that this form is described as being unarmed, 
there is nevertheless a single weak spine on the type specimen, which 
is apparently a young and immature branch. The spine might easily 
be overlooked as it is somewhat hidden by leaves, the specimen being 
fastened to a herbarium sheet. 
The leaves on the Academy specimen of this form from Barrington 
Island are very small and for the most part are oblanceolate or spatu- 
late in shape with strongly revolute margins. The bases of the leaves 
may be either obtuse or acute, and the apices are sometimes obtuse. 
The specimen from Duncan Island in the Academy collection has 
leaves which for the most part are narrowly spatulate or oblanceolate 
in shape. In some instances they are nearly linear, a condition appar- 
ently brought about by the strongly revolute margins of the leaves. 
The bases and apices may be either acute or obtuse, both kinds of 
leaves occurring on the same specimen. The specimen described by 
Robinson as typical is immature and the leaves are all lanceolate. 
There is upon the same herbarium sheet, with the type specimen of the 
form duncanensis, still another specimen, No. 42 (hb. Gr.) from Charles 
Island which Robinson^ assigns to the form carolensis with a question. 
I can find but little difference in these two specimens as the leaves are 
practically identical in shape on the two. Lanceolate leaves occur on 
both the type and the Academy specimens of the form albemarlensis 
as noted above. The leaves on the specimen from Jervis Island are 
spatulate for the most part, and the leaf margins are less inclined to 
be revolute than on any other of the Academy specimens asvsigned to 
this form. Leaves which are spatulate in shape are thus seen to occur 
on all of the Academy specimens assigned to this form, and they also 
occur on all three of the forms previously considered, viz., albemarlen- 
sis, bindloensis, and carolensis. 
' Stewart, op. cit. 83. 
^ Op. cit. 159. 
