A New Fern from Rota, Mariana Islands 
W. H. Wagner, Jr. 1 
About 75 species of ferns are known from the 
Mariana Islands. Of these the majority are com¬ 
mon and wide-ranging. Only a few species are 
endemic or generally considered rare. 
The only previous records of the cosmopoli¬ 
tan and very large genus Lastrea in the Marianas 
are of the common species with much-dissected 
fronds: L. Torresiana (Gaudichaud) Moore 
{—Polystichum Torresianum Gaudichaud, 
Freyc. Voy. Bot. 33. 1827) from Guam, and 
the similar L. ornata (Wallich) Copeland 
(=Phegopteris ornata Fee, Hosokawa, Nat. 
Hist. Soc. of Formosa, Trans. 26: 233. 1936) 
from Alamagan, Sarigan, and Anatahan. The 
following is a species of Lastrea with bipinnati- 
fid fronds, known from eight complete fronds 
obtained from two separate plants on the island 
of Rota, collected by D. F. Grether of the Uni¬ 
versity of Wisconsin. 
Lastrea Gretheri n. sp. 
Fronde pinnata, chartacea, pubescente, utraque facie 
glandulifera, 3 7 cm. alta, 10 cm. lata; stipitibus 11 cm. 
aids, minute pubescentibus, sulcatis, stramineis, sed 
basi atrocastaneis, et paleis atrocastaneis pubescentibus 
linearibus acuminatis vestitis; pinnis ad alam 1 mm. 
latam pinnatifidis, fere sessilibus, 5.5 cm. longis, 1.0 
cm. latis; pinnis basalibus non brevioribus; segmentis 
5-6 mm. longis, plerisque oppositis, oblongis, obtusis, 
integris, marginibus deflexis; venulis 6-8-paribus, li- 
beris, simplicibus; soris parvis, 3-5-paribus, ad seg- 
menta submarginalibus, confertis; indusio crasso, cas- 
taneo, persistente, glanduloso; sporis nigris. 
A fern of the habit of Cyclosorus dentatus (Forsk.) 
Ching. Rhizome not taken but form of stipe bases 
indicating a creeping rootstock. Scales of stipe-bases 
linear-acuminate 3-7 mm. long, 0.5-1.0 mm. broad 
at base, shiny dark-brown, provided with numerous 
needle-like pale hairs, 0.1 mm. long. Fronds 4-5, 
oblong-lanceolate, 37 (33-41) cm. tall, including the 
stipe, 10 (9-12) cm. broad at the middle. Stipes 11 
(9-13) cm. long, 1.5 mm. thick in the middle, drying 
deeply sulcate, atrocastaneous in lower 3-6 cm., shad¬ 
ing into pale straw-color, densely beset with pale hairs. 
1 Department of Botany, University of California, 
Berkeley. Manuscript received October 28, 1947. 
Rachis drying quadrate-ridged, and deeply sulcate, 1.3 
(1.2-1.5 mm.) thick in the middle, densely clothed 
with white hairs except on ventral face where they 
are red-brown. Pinnae 26 (25-28) pairs, opposite or 
slightly subopposite except at tip, all fertile, lower 
several pairs pointing downward or at right angles to 
the rachis, the lowest of same size or but slightly 
smaller than those above. Largest pinnae 5.5 (5.0- 
6.0) cm. long, 1.0 (0.9-1.2) cm. broad at base, nearly 
sessile. Segments deflexed along margins, mainly op¬ 
posite, rounded oblong, entire, 5-6 mm. long, 2.5 mm. 
broad at base, usually 18 pairs, costal wing 1 mm. 
wide. Pinna-tips 5 (4-6) mm. long, 2-3 mm. broad 
at base, narrowing to a rounded point. Lamina char- 
taceous, soft in the living state, gray-green, abundantly 
covered with pale hairs which are longer on the costa 
dorsally, and of brown color on the costa ventrally, 
and with numerous glands with yellow to orange- 
brown expanded tips on both surfaces. Veins entirely 
free, mostly opposite and simple, 6-8 pairs. Sori sub¬ 
marginal, crowded, about 0.5 mm. in diameter, 3-5 
pairs, confined to segments as in Cyclosorus interruptus 
(Willd.) Ching, and dark-brown. Indusia thick, per¬ 
sistent, red-brown, reniform, with numerous globular 
shining dark-brown glands grouped near the sinus and 
smaller, much paler ones on wings. Spores jet black. 
Type: Growing on bare coral-limestone rock 
in a crevice in a rather exposed situation on a 
bank along a road at 800 ft. altitude on the 
north slope of the plateau of Rota, Mariana 
Islands. July 28, 1946. D. F. Grether 4468. 
University of California Herb. no. 736319. 
Duplicates are deposited at the U.S. National 
Herbarium and the Bernice P. Bishop Museum. 
Of Pacific ferns, this new species is most simi¬ 
lar to Lastrea Harveyi (Mettenius) Carruthers, 
of Melanesia and Polynesia; the present plant 
differs from it in smaller size, somewhat thicker 
texture, lack of strongly dwarfed basal pinnae, 
much more abundant hirsuteness, and in the 
presence of numerous glands. Of other related 
plants, L. euaensis Copeland of Tonga is nearer 
to L. Harveyi than to the present species. L. 
Margaretae (E. Brown) Copeland, of Rapa, 
differs in the thicker texture, dwindling pinnae, 
and broad gray-brown scales of the stipe-bases. 
C214] 
