155 
Var. serratus, Huds. (labelled P. serrudatus, Schr.) Spec. f, 
sent by Nolte from Schleswig-Holstein. This is merely a form, 
‘not a true variety. : 
17. *P. decipiens, Nolte. For. sp.; spec. from Sweden, 
coll. and com., Dr. G. Tiselius, of Stockholm. 
18. P. densus, L., (P. oppositifolium, DC.) For. sp., 
spec.33 ; ui 
19. PP. fluitans, Roth. For. sp.;.spec..4; Cuba, Eu. and 
Africa. 
20. *P. gemmiparus, Routine, in Huse (2. gubilius, Ls. 
var. (?) gemmiparus, Robbins in Gray’s Manual); type. spec. 
Ex. Herb. Dr. Robbins... 
21. P. gramineus, L. (P. Jerteetpihyllus Schreb.) Spec. 12; 
Am., N. Eng., N. Y., N. J., Nevada; for., Gr. Brit. France. 
I include in this the so-called viilethils heterophyllus and 
_ graminifolius. *Also spec. of the type form and varieties, Ex. 
Herb. Dr. Robbins. 
* Var. (?) spathuleformis, Robbins, of Gray’s Mains type 
spec., Ex. Herb. Robbins, coll. in Fresh Pond, Camibehige, 
Mass. This was at first called P. spatheformis by Tuckerman. 
I consider it only a form of P. Zz2z, M. and K. 
Var. maximus, Morong. Two spec. contributed by Prof. 
Tuckerman, and marked by him P. /onchites; and also one spec. 
contributed by Prof. Porter, under the name P. rufescens, are both, 
in my opinion, P. gramineus, L., var. maximus, mihi. 
22. FP. Hillit, Morong. One spec. from N. Y., coll. W. H. 
Leggett, and one spec. from Mich, coll. E. J. Hill. 
23. P. hybridus, Michx. Spec, 18; from N. Eng. to N. 
Mex.; * one spec. Ex. Herb. Dr. Robbins. 
24. *P. Llinoensis, Morong. Spec. coll. R. I. Cratty, in 
Iowa, and H. N. Patterson, in Illinois. 
25. *P. lanceolatus, Sm. Spec. from England, coll. Mr. 
A. Bennett, of Croydon. A sp. peculiar to Gr. Brit., not yet 
found in fruit. 
26. LP. lonchites, Tuckerman. For the present this sp. is 
allowed to retain the name by which it has been known in this 
country ever since it was described by Tuckerman in Silliman’s 
Journal thirty-seven years ago; but I am quite satisfied that it is. 
