~83- 
ments. Torka does not state whether these plants produced sporophytes or 
not. In 1914 he distributed excellent specimens of his var. natans (9, No. 51) 
from the Zablocie locality. These present the appearance of a slender aquatic 
R. fluitans, as this species is usually understood. 
It is unfortunate that Torka 's evidence is not more conclusive. Although, 
in his cultures, the tips of the thalli often detached themselves and floated on 
the water, nothing is said about their growing while in this condition. It is 
implied, in fact, that the floating fragments carried on a very precarious existence 
unless they came in contact with some firm substratum. The mere fact that 
they remained green for a while would hardly show that they represented a 
true aquatic form of R. Huebeneriana. In order to prove that such a form had 
been produced it should have been shown that the plants in question were cap- 
able of continuing their growth and development in their new environment. 
With regard to the Polish specimens of his var. natans the evidence is lacking 
that these actually represent R. Huebeneriana. The only way in which this 
could be proved would be by means of morphological characters either in the 
thallus or in the spores. No such characters are given, and, although the attached 
plants are said to resemble the attached fragments of R. Huebeneriana in the 
water cultures, these fragments (as represented by Torka 's figure) are hardly 
representative of R. Huebeneriana as it normally appears. The case is further 
weakened by the fact that he does not report the normal terrestrial R. Hueben- 
eriana in the vicinity of the var. natans, although he cites a single station for 
it at a somewhat distant Polish locality. 
In 1916 Donaghy (1) published a series of interesting field observations 
on R.fluitans, as it occurs in Indiana. He reports that the so-called terrestrial 
form is uncommon in his region but notes its o:casional appearance "on mud 
flats and wet fields during the autumn." This form produces sporophytes in 
abundance. The aquatic form is abundant around Angola, Fort Wayne, and 
Terre Haute, where "during the summer and autumn mats .... can be 
found floating in ponds and sluggish streams, "sinking to the bottom in the w'nter 
and remaining there until spring. Although plants beneath the ice remain un- 
injured, those "frozen in the ice are much winter-killed, the apical ends alone 
remaining green." During "spring these plants make rapid growth, and by 
summer patches of thalli again dot the ponds and streams." When, owing to 
evaporation, the water becomes low, "mats of plants are" often "washed upon 
the wet edges of the ponds, " and "in favored places the thalli coming in contact 
with the wet soil develop rhizoids .... and open air-chambers." Whether 
such plants ever develop sexual organs and sporophytes remained uncertain, 
Donaghy 's evidence on this point being wholly negative. He reports a case 
where plants "remained alive in wet shaded places .... in contact with the 
earth sufficiently long to fruit," and yet "no sporophytes were formed." 
In Donaghy 's opinion these sterile terrestrial plants, derived from the 
aquatic plants, were distinct from the so-called terrestrial form of R. fluitans, 
and he failed to find the latter on the mud of ponds where the aquatic form was 
growing. He concludes from his observations that "it seems very doubtful 
