KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55. N:0 5. 141 



field, by larger fruits, and by scattered subepidermal bast-bundles and stretched epi- 

 dermis-cells in the stem. 



Distribution. North America, many stations in U. S.: Mass., N. York, N. 

 Jersey, Minn., Mich. (hb. Stockh., Uppsal., Lund.) and Canada, Plevna, Ont., 02, 

 Fowler (hb. Stockh.). 



Subsectio 16. Alpini (Grabbn., 1. c. pag. 70. incl. P. linguatus etc.) Hagstr. 



Caulis teres, sub foliis floralibus simplex. Folia natantia obtusa basi attenu- 

 ata brevipetiola (petiolns lamina non longior); submersa evaginata sessilia linearia 

 — lanceolata — ovata (rarissime) vel ovalia (P. stylatus), multinervia. Ligulce mem- 

 branacese apice rotundatse — emarginatse fissse ejugse in spatio intermedio paucinervise 

 (2 — 4-nervi8e in P. alpino). Pi5<i7Z?tTO stylo elongato tenui compresso, stigmate oblongo. 

 Fructus lenticularis carinatus rostratus (P. alpinus). 



P. alpinus differs from the Amplifolii so considerably as to deserve to be put 

 into a separate group, to vs^hich P. stylatus Hagstr. also may provisionally be re- 

 ferred as a transition form to the Amplifolii. Its fruit is still unknown, but the styles 

 remind of P. alpinus. 



A longitudinal section of the ripe fruit shows that the putamen is upwards 

 endowed with a thorn or point forming the kernel of the always rather promin- 

 ent beak. 



The turios of P. alp. are noticeable. They are formed by a single shoot in 

 bud state (from the third node and so on) in the top of the rhizome without incras- 

 sation but with thickened scales, which serve as reservoirs for stored food. 



The group is poor in schlerenchymatous tissue and associates anatomically as 

 well as morphologically closely with the next following. 



P. nlpiiuis Balbis. 



Miscellanea botanica, in Memoirs de 1' Academic des sci., litt. etc. de Turin. 

 1804, 329. — P. annulatus Bellardi, Stirpes novae etc. 1. c. 1804, 447. — P. semi- 

 pellucidus Koch et Ziz, Catalogus plantarura etc., 1814, 5, 18.* — P. rtifescens 

 Schrader ap. Chamisso, Adnotationes qusedam etc., 1815, 5 — 6. — P. ohscurus DC, 

 Flore fran<;aise etc. Vol. VI, 1815, 311. — P. purpurascens Seidl in Presl, Flora 

 cechica, 1819, 251. — P. microstachys Wolfgang ap. Schultes, Mantissa in Vol. III. 

 etc., 1827, 360. — P. ohtusus DucROS ap. Gaudin, F1. helvetica etc., 1828, 468—469. 

 - Fig. 63. 



The two earliest descriptions of this species are very dissatisfying, and the fi- 

 gure, added by Bellardi to the description, resembles with its sharp-pointed leaves 

 more P. gramineus than P. alpinus. Koch and Schrader — Chamisso first state 



' Pag. 5 signed only witli Koch's name. 



