pdf 31 MB - BSBI Archive

THREK NEW LASTREAS FROM ASSAM. 327
the shortest ; aori one to each group of veins on lowest veinlet near
the costa, which veinlet in fertile lobes points to the sinus, but often
stops considerably short of it or is obscure beyond the sorus, but in
barren lobes may be prolonged like the others, or rarely 2-3 in
lowest pair of lobes : involucres entire, persistent.
Collected by Mr. Gustav Mann, Conservator of Forests, Assam,
in Assam—in Bor Bhil, Upper Dehing Forest, Lakhimpur, April,
1887; in the Garo Hills, at 1000 ft. elevation, "on wet rocks! " in
April, 1888, and November, 1889 ; and in the Nambar Forest, in
January, 1888. Appearance, when pressed, somewhat like that of
Asplcnium {Athijriitm) niijripes Mett.
Nephrodium (La.strea) subtriangulare, n. sp. — Cawiex
erect, densely clothed with linear chestnut scales ; stipes tufted,
wiry, as long as or longer than frond, round below and slightly
channelled above, as is also the main rachis, clothed at base with
dark brown linear lanceolate scales longer than those on caudex,
sparser and paler upwards ; main and secondary raclnses slightly
squamifeious, secondary rachises grooved above and on sides, round
below; frond 14 in. long by 10 in. broad, very broadly lanceolateacuminate,
bipinnate ; pinme opposite at base of frond, gradually
becoming alternate upwards, 8-10 pairs free, lanceolate-acuminate,
falcate, all unequal-sided, and all except lowest pair very slightly
narrowed at base ; lowest inferior pinnules on lowest pinnae very
much shorter than next three or four pifinnles numerous, lower,
;
subsessile, with slightly winged stalks, upper,— sessile, gradually
becoming decurrent on rachis, and towards apex confluent : /linnules
lanceolate, falcate, rather blunt-pointed, the entire apex slightly
toothed ; lobes or see/ments inclosing groups of veins increasingly
distinct towards base of pinnule till the dividing sinus sometimes
nearly reaches costa, usually with only one tooth corresponding to
uppermost veinlet of group, and that pointing upwards and sometimes
inwards to next lobe above, so as to lie within general outline
of jnnnules ; texture herbaceous, surfaces glabrous ; nuns invisible
above, except cost;e, not raised beneath, pinnate or rarely bipinnate
in lobes, and terzninating within the margin ;
sori—on upper pinnsB
nniserial, near the costa on inner veinlet of each group of veins,
on lower pinna3 becoming more copious, and borne on both sides of
main vein of segment; inrolucrrs entire, shrivelling, dark-coloured.
Collected by Mr. Gustav Mann, Conservator of Forests, Assam,
in Assam, at Laukot, southern face of Khasi Hills, HOO ft. elevation,
in September, 188M, and i)i the Jaintea Hills, at 3000 ft. elevation,
in March, 1890. Mr. Mann says the plant ia rather rare, and he
would place it between Xephrodinm [Lastrat) assainrnsc (Hope) and
y. (Lustreii) l''ili.i--vias (Rich.), var. 2 vorntulis (Clarke in Trans.
Linn. Soc, 2nd »Ser., 13ot., vol. i., p. 619). The present species
seems to me, however, quite different from iV. asstnnensc, and it can
be easily distinguished from Clarke's plant by the scales, shape of
frond and cutting of the pinnules, by the veins, and by being
soriferous on all tlie pinnaj. In Clarke's fern, whicii hn^ no allinity
to .V. l''ili.rui(is, and which was previously nanied by Moore, fioni
Utddome'b specimens, LastrcK odontoloiiut, sori are never found on