264 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
ultra in lobos 4-5 oblongos apice rotundatos partito, lobis in parte 
media viridibus sed margine albescentibus vel tardius erubescentibus ; 
staminibus 4—5 ; antheris 0.5 mm. longis ; ovario triquetro elongato ; 
fructu 2.8 mm. longo lanceolato apice tenui falcato e calyce longe 
exserto. YV infield, Ivansas, Paul P. T VJiite, 10 October, 1898 (type 
in hb. IT. S. nat. mus.; fragment in hb. Gr.). This species although 
as yet known from a single individual seems so well marked as to 
merit description. In habit and foliage it most nearly approaches 
/ . prolificum, Robinson. The fruit, however, is very different in 
foim and as in P, exsertum , Somali, protrudes far out of the calyx. 
P rom the latter species, P. leptocarpum is readily distinguished by 
its much smaller flowers and fruit, which are scarcely half as large 
as in P. exsertum. 
P. (§ Avicularia) caurianum, spec. nov. Annuum gracillimum 
glaberrimum a basi ramosum et floriferum, caulibus subfiliformibus 
piostiatis vel adscendentibus subsimplicibus vel plus minusve ramo- 
sis 12-25 cm. longis foliosis, ocreis brevibus scariosis ad insertionem 
folii ulti a mediam partitis, lobis obtusis vel acutis saepe laoeratis sed 
baud in fibras dissolutis; internodiis pergracilibus maturitate 1-3 cm. 
longis quam folii longioribus; foliis anguste ellipticis vel oblongis 
1—1.6 cm. longis, 3—5 mm. latis integerrimis tenuibus penniveniis 
apice rotundatis basi in petiolam filiformem attenuatis; floribus 
axillaiibus teinis vel quinis quam ei Polygoni avicularis minoribus 
graciliter pedicellatis basi turbinatis; calyce erubescenti, lobis orbi- 
cularibus tenuibus margine petaloideis plus minusve patentibus ab 
achaenio nigro-brunneo triquetro minutissime punctato conspicue 
superatis ; staminibus 5 inclusis.— Hushagak, British Columbia, 18 
August, 1882, McKay, no. 49 (type in hb. Gr. and hb. U. S. nat. 
mus.); also on the middle and lower Kuskawin, Alaska, F. C. 
Hinckley , August, 1898 (hb. Gr.). 
Although in technical characters this species is very near P. 
aviculare, L., it may be readily distinguished by its very slender 
almost filiform stems, slightly smaller flowers and achenes (2.6 mm. 
long), and by the form and venation of the leaves. These in P. 
aviculare , when observed in transmitted light, are seen to have firm 
straightish lateral veins departing from the mid-nerve at an angle of 
about 30°. In P. caurianum on the other hand the lateral veins 
are much finer and leave the mid-nerve nearly at right angles, curv- 
m g foiwaid and anastomosing freely before they reach the margin. 
