Haynes: THE GENUS SPHAEROCARPOS ot7 
mens from the same locality, Sphaerocarpos “stipitatus Bisch. 
replaces S. Berterii Mont. (S. Berterot of Stephani’s Species 
Hepaticarum). To the five species thus remaining from Stephani’s 
list, a sixth, the new species from the state of Washington, alluded 
to at the outset of this paper, is added below. 
It should be remarked, perhaps, that Sphaerocarpos Notarisii, 
Mont.* was, a few years after its publication, referred by Montagne 
to its proper genus Rve//a. 
The species of Sphacrocarpos are certainly among the simplest 
and most interesting of the Hepaticae and the importance of the 
genus from the evolutionary and phylogenetic point of view is 
clearly set forth in the following quotation from Professor Camp- 
bell :+ 
‘* From a review of the preceding account of the Liv verworts, it brs be apparent 
that these pl seat pel gentle the thallose forms, constitute a very ill-defined group of 
organisms, one erging into anot er by almost insensible gradations, and 
this is | rue mer th selves, but applies also x eir connec- 
ion he Mosses and Pteridophytes. The fact that the degree of development of 
enitiewiphies os ae ophyte does not always co — nakes it oes difficult to de- 
termine which forms are to be regarded as the t pri gt while Riccia is 
ee onably the simplest as regards the spropbyte gone gametoph ie is very muc 
more specialized than that of Ameura or Sphaerocarpus. ‘The latter is, perhaps, on the 
whats the simplest form we know, and we can ssuivee e how from similar forms all of 
other groups may have developed. The done recurrence of the two sided 
i ; ition in so many form s it 
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probable that the primaiiive fea had this type of diene cell. From this diPicialion, 
form, in which the thallus was either a single layer of cb or with an imperfect mid- 
rib like Sphaerocarpus, three lines - sb ap ages may be assumed to have arisen. In 
one of these the differentiation wa: inly in the, tissues of ake gam a and 
sporophyte remained compara tively pee although showing an PRET the m 
specialized for The — of this type is iVestrated in the germ 
h f 
m that they have n deriv = ) 
more specialized thallus of the Marchantiacea Sphae ape ger showing as it does 
points of affinity with both the lower Mar chenslalas and soar nacrogynous Jungerman- 
niales, keene Fe more nearly than any other known form this hypothetical 
type. - ts eos , however, simple as it is, is more “perfect than that of Riccza, 
an ur hyenas sis is correc ct, the Marchantiales m pete e been derived from 
Splaeracrpu -like forms in which the sporophyte was still s ples th an that of ex- 
isting Asean that this is correct, the farther evobetios of the Ma rchantiales 
is ft ona and the series of forms from the lowest to the hi plete.’ 
“In the second series, the Jungermanniales, starting with Sphaerocarpus, the line 
leads through Aneura, Pellia, and similar simple tha wit ee to several types with 
more or less perfect. leaves —e. £; reed sta, Fossom ubi 
These do not constitute a single series, but have aseune de veloped independently, 
and it is quite probable that the synod foliose Jungermanniaceae are not all to be trac ced 
* In De Not. Mem. R. Accad. Torino IT. ey Bees 18309. 
{ Campbell, D. H. The structure and development of mosses ‘dod ferns 157-159. 
1905. [ed. 2 
