61 113 
Subgenus 4. Lastrea Bory, emend. C. Chr. 
Biologiske Arbejder tilegnede Eug. Warming p. 79. 1911. 
This subgenus is nearly identical with the group of Dryopteris opposita mono- 
graphically dealt with in my former papers on American species of Dryopteris 
(quoted above pag. 55). I have there in some details mentioned the charaters of 
the group, and I have only a little to add to my earlier treatment. Still my 
delimitation of the group must be somewhat changed, partly by including some 
species, which have not a decrescent lamina, partly by excluding some few species, 
which I now refer to the subgenus Glaphyropteris. 
The character: a lamina decrescens is, like all other single characters, not 
available as standard-character, which all species of this subgenus have in common 
and which is found only here. It is evident that a species as JD. blanda (Fée) 
C. Chr. is a near relative of D. oligocarpa, although it has not the lamina nar- 
rowed downwards. Our common JD. thelypteris is another instance of a species 
having a non-attenuate leaf. Still such species are exceptions which affirm the 
rule. Out of the 118 species enumerated below only 3 or 4 have not auriculiform 
pinne. On the other hand species with a lamina decrescens are to be found also 
within other subgenera, f. inst. Glaphyropteris and Steiropteris. In some species of 
§ Cyclosorus, f. inst. the typical D. mollis, the lamina is so much narrowed down- 
wards as in most species of $ Lastrea, and the same can be said on D. Saffordii 
a species of § Eudryopteris. 
The best and most constant character of § Lastrea is the venation, as ex- 
plained in my “Revision”. The veins are always free, as a rule simple (in some 
few species normally furcate), the basal ones nearly always reaching the margins 
above sinus and not separated by a cartilagineous membrane as in species of 
§ Steiropteris and Cyclosorus. The frequent occurrence of sessile glands on the leaf- 
tissue beneath and of aérophores at the base of the pinnz are also characteristic 
for the subgenus. In this paper I have excluded those species having aérophores at 
the base of the segments and referred them to $ Glaphyropteris, viz. D. Canadazii, 
D. Thomsonii and D. macradenia. Most species are rather hairy by simple and, as a 
rule, unicellular hairs; only in some very long-hairy species (D. mertensioides, D. Rui- 
ziana, D. nitens, D. multiformis and some others) the long hairs consist of 2—4 
cells, but such hairs are not very like the short, pluricellular hairs so characteri- 
stic in species of $ Clenitis. The sori are in several species exindusiate, in others 
furnished with a small, rarely persistent indusium. 
Since the publication of my earlier papers I haye examined numerous speci- 
mens of species belonging to $ Lastrea, some of which belong to species previ- 
ously unknown to me and some others to species new to science. In the following 
pages I give another supplement to my first paper, and the number of species is 
now increased to 120. As seen from that number the subgenus is extraordinarily 
