158 
P. striatus. A spec. so labelled, from Chili, S. A., is not the: 
real P. striatus, Ruiz. et Pavon., but P. pusillus, L. 
47. P. tenuicaulis, F. Miller. Two excellent spec. of this 
rare Australian sp., one from Formosa, coll. Oldham, and the 
other from India, coll. Hook. fil. and Thomson. 
48. FP. trichoides, Cham. For. sp.;. one excellent spec. 
from Eu. 
49. P. Tuckermani, Robbins. Spec. 5; N. J., N. Y. 
N. Eng.; *type spec. Ex. Herb. Dr. Robbins. 
50. PP. varitfolius, Thore. For. sp.; spec. 1, France. 
51. *P. Vaseyt, Robbins. Spec. from N. Eng. and Canada. 
52 P. WRIGHTII, n. s. Leaves all submerged, alternate, the 
blade elliptical, the largest 4% inches long, 4 or 5 lines broad at 
the widest part, tapering into a petiole 1% inches in length, and 
abruptly acute or acuminate at the apex, the midrib thick and 
compound, with 5 or 6 lateral nerves on each side, margins en- 
tire, cross veins numerous and sloping slightly upwards; stipules 
scarious, obtuse, 1 to 2 inches long; peduncles clustered at the 
top of the stem, slightly thickened upwards, 1% to 134 inches in 
length; spikes 1 to 2 inches long, narrow cylindrical, the fruit 
crowded; nutlets obovate, about 134 lines long by 1% lines 
wide, three-keeled on the back, with a remarkable projection or. 
hump on the upper part of the face, and two lateral teeth or pro- 
cesses at the base (vid. figures 1 and 3 in the plate), the sides 
flattened; style short, apical; apex of the embryo ‘pointing 
directly towards its base. PLATE “LIX. 
Collected by C. Wright at the Loo Choo Islands, in the Exp. 
of Ringgold and Rodgers, in 1853-6. 
The plant is without roots, the fragment being about 16 
inches high. A similar specimen is in the Herb. of Dr. Asa 
Gray at Cambridge. In the Torrey Herb. it is labelled P. rufes- 
cens, Schrad., but it is essentially different from that sp., though 
bearing a general resemblance to it. P. rufescens has leaves 
obtuse at the apex, while here they terminate abruptly in an acute 
or acuminate point; and in this sp. the cross-veining is much 
closer. The fruit, however, forms the most remarkable feature 
of Wright’s plant, being totally unlike that of rufescens, or of 
any other sp. with which I am acquainted. 
