404 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
TYPE LOCALITY: Jamaica.! 
DistrisuTion: Apparently confined to the high peaks of the Blue Mountains of 
Jamaica, altitude 1,700 to 2,220 meters. 
Intustration: Schkuhr, op. cit. pl. 7 (as Grammitis myosuroides). 
The grounds for naming this species as above were given briefly by the writer in 
1905 ? and have been restated, necessarily at some length, under the last preceding 
species. To be compared with Schkuhr’s illustration are the Jamaican plants shown 
in plate 12 and figure 10, all of which represent P. delitescens. The writer’s plant 
illustrated in figure 10 in particular is seen to agree closely with that of Schkuhr. 
Both represent a somewhat extreme form of P. delitescens, in which nearly all of the 
segments are distinct. Other specimens (for example, a part of those shown in pl. 12) 
have the upper lobes or segments somewhat confluent, the apex thus being less deeply 
incised. But it will be seen that in all of these conditions 
there is no sharp differentiation of a caudate fertile tip and 
that the sori are borne also upon the larger segments or 
lobes in the middle part of the blade. In other words, 
the apices of P. delitescens are usually deeply serrate or at 
least never assume the form characteristic of P. myo- 
suroides, in which species there is invariably a sharp 
differentiation between the sterile and fertile portions, 
the latter being slender, elongate-caudate, and shallowly 
sinuate crenate. Polypodium delitescens differs otherwise 
from P, myosuroides in its approximate, nearly deltoid 
(instead of distant, oblong) segments and in the absence 
of dark bristle-like hairs upon the rachis and leaf margins. 
The sori, also, from their position upon separate or only 
partially fused lobes or segments are usually more or less 
distinct, never wholly losing their individuality, as 
Jenman has pointed out. The underside of the rachis 
is deciduously glandular-pubescent, instead of bristly- 
pubescent. The leaf tissue is much more opaque than 
that of P. myosurovdes. 
These two species are thus seen to be very dissimilar to 
each other, and their confusion in the past must be ascribed 
partly to lack of good material. That they should have 
Fic. 10.—Polypodium delitescens, heen mixed in the original collection is not remarkable, 
from Blue Mountain Peak, since they are often found growing in close association 
Jamaica (Mazon 1513). a, En- yon the mossy branches and trunks of forest trees. Such 
tire plant; b, section of fertile ue : F 
portion. a, Natural size; , ® Condition is not uncommon among many of the lower 
scale 2. crytogams, notably the Hepaticae, and has been observed 
repeatedly by the writer in the case of various small 
tropical American species of Polypodium and even of Elaphoglossum, where 
conditions have been unusually favorable to a luxuriant growth of related species 
requiring a similar habitat. 
As noted above, P. delitescens is apparently confined to Jamaica. The following 
specimens are in the U. S. National Herbarium: 
Jamaica: Monkey Hill (above New Haven Gap), alt. 1,800 meters, Mazon 2732, 
2750. Near New Haven Gap, alt. 1,700 meters, Underwood 962, 1019. Near 
' The actual type will be Schkuhr’s original plant, if extant; otherwise it will be 
Maxon 1513, U. 8. National Herbarium 427770, as previously designated. 
3 Bull. Torrey Club. 32: 73-75. 1905. 
