98 
Summary. 
Two different species of plants are included in the 
name Glyceria aquatica , viz. Air a aquatica L. (= Catabrosa 
a. PB.) and Poa aquatica L. (= Glyceria spectabilis Meet. 
& Koch). Presl transferred Air a aquatica L. to the 
genus Glyceria in his FI. Cecliiea 1819 and called it Gl. 
aquatica. This combination is a valid one according to the 
rules of botanical nomenclature art. 56 and can not be 
rejected on the basis of the rules expressed in articles 
51 — 55. The combination in question has later been 
used in Koch. Synopsis FI. Germ. & Helv. Ed. II. 1844. 
in Hartm., Handb. i Skand. Fl. Ed. VI 1854 etc., and 
as late as 1917 in Krok & Almqu.. Svensk FI. 
In 1820 the combination Glyceria aquatica — Poa 
aquatica L. was made by Wahlberg in FI. Gothob. 
Being homonymous with Presls combination Wahlberg ? s 
Glyceria aquatica can not be accepted but should be 
placed with the synonyms. 
The first edition of Hartmans Handb. i Skand. FI. 
was published in the same year,, viz. 1820. Here the 
two plants are referred to the genus Molinia. Aira 
aquatica L. is called Molinia aquatica , a name already 
given by Wibel in Primitiæ Fl. Werth. 1799. Since 
Poa aquatica could not retain its specific name when 
put in this genus, a new one had to be given it, and 
the plant was called Molinia maxima by Hartman. Thus 
M. maxima is a valid combination according to the ar¬ 
ticles 53 and 56. 
That Glyceria spectabilis — a name younger by three 
years — has been the one generally accepted, is due 
to the circumstance, that Hartm. Fl. Ed. II, 1832, is 
quoted as the first place of publication of Molinia 
maxima in spite of the fact that this latter name was 
already proposed in Ed. I, 1820. 
Thus the proper name to be applied to Poa aqua¬ 
tica L. is Glyceria maxima (Hartm., 1820) n. comb. 
