112 



J. O. IIAGSTBÖM, CRITICAL RESEARCHES ON THE FOTAMOGETOXS. 



The species shows no tendency to transform thc top-most involucral leaves. 



The pistil has a short style with a more or less beak-shaped prolongation 

 above, like P. mucronatus, and the rostrum of the fruit, therefore, presents a charac- 

 teristic hook-formed curvature backwards. The fruit-flesh or epicarp is very thin 

 causing the fruit to exhibit lateral pits. This mav, however, be an accidental feature. 

 The size of the fruit is recorded to be very considerable (Bennett: »2 1 lines by 



1 \ in. broad 



Graebker: »fruetus 4,5 mm longi, 3 mm lati» ). Allowing for the 

 misprint (»in.» for lines) I am nevertheless unable to understand 

 how such measures could be arrived at on so small pusillus-\ike 

 fruits. 



The specimens from Santiago (see below!) are endowed 

 with turios. They consist of somewhat swollen tops of branches 

 or short branches, 25 mm long, the lower free leaves of which 

 are considerably reduced in size, spreading and scarcely overreach- 

 ing the obtuse inner ones, clasped by sheaths of equal length. 



Distribution. South America. Chile, St. Jago?, PHiLirrr 

 (hb. Stockholm.); Brazil, Rio de Janeiro, Glaziou (hb. Stock- 

 holm.); Uruguay, Montevideo, 79, Arechavaleta. Probably it 

 does not transgress the 35° S. L. N. America, Canada, New 

 Foundland, and Sable Island, Macoun (hb. Hann.). Cuba, 

 Wright, 2305 (hb. Stockholm.). 



The above mentioned gigantic form is gathered by P. 

 Dusen in Paranä: mouth-district of Rio Cubatuo (brackish wa- 

 ter), Vi 1912 (hb. Stockholm.). I have named it: 



f. pusilloides n. f. — Caulis valde elongatus metralis, com- 

 pressus, internodiis ca. 10 cm longis. Foliis majoribus, 90—120 



x 2- 



Fig. 17. /'. Aåehersonii 

 Ar. ]!i.sm i i A, Top of a stena 

 Ii af, ,'. /.'. TransveTse bi c- 

 tion throngfa the lacanar part 

 "t .i gtem Ii af at the middle, 



»i, midvein, stf, 



btmdles <'. Transverse sec- 



tion of tlir pedanele, str, 



basl bnndli 9, Y D, Pistil, 



idi eii w, V'. /••'. Frnii 



-3 mm, flexilioribus iis P. pusilli simillimis. 

 One could almost expect the mechanical tissue to be more 

 richly or strongly developed than usually is thc case, but we 

 find no tendency to this, rather to the contrary. 



V. attcniintus n. 



(spec. v.) h} T br. 



(P. Aschersonii Ar. Benn. x polygomts Cii. & Schl.). 

 Caulis c. 0,5 m altus subcompressus, simplex vel ramulo- 

 sus, ab axillis foliorum floralium prolongatus ramulis prima) — secund;e ordinis, intci- 

 nodiis 20—30 mm longis. Fulia rigida linearia apice sensim attenuata, modo P. 'pol;/- 

 fjoni, acuta, in superiore parte trinervia, infra medium ut plurimum 5 — 7-ncrvia; 

 ii media reticulosa; fasciculi libriformes mechanici mediani vt margiuales validi 

 fere ut in P. polygono, lAgulas cito putrescentes, 10—12 mm long», in parte media 

 6— 7-nerviee. Pedunculw subteres, 20 — 30 mm lougus. Spica 3—4 verticillata. Pistil- 

 luiii Btigmate oblongo. — Fig. 48. 



I ti all specimens here axailahle the pollen is quite sterile. In the vegetative 



