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A STUDY OF TETRAPLODON AUSTRALIS. 
By I. Hagen. 
Tetrciplodon australis Sulliv. & Lesq. has been very little studied. 
This fact is accounted for by the circumstance that the specimens in the 
various herbaria were collected for the most part too late in the season and 
hence in a condition unfavorable for study. I am, however, happily in pos- 
session of fine material collected at my request by Mr. Severin Rapp, at 
Sanford, Florida, during the month of December, 1904. An examination of 
this material has furnished the details which enable me to determine its rela- 
tionship decisively. 
Why the authors of the last half of the nineteenth century placed this 
species in the genus Tetraplodon, I have never been able to comprehend, 
and a study of Mr. Rapp's collections has shown me that this genus is pre- 
cisely that one of the sub-family Splachnae with which it has least in com- 
mon. There are important differences in nearly all parts of the sporophyte: 
— the seta is soft and hyaline in ' T. australis , solid and colored in the 
other species of the genus ; the columella is exserted in the former, included 
in the latter; the teeth which are bigeminate in the other species of Tetra- 
plodon are geminate only in T. australis , and, in addition, in this latter 
they have central cavities, though solid in the other, a condition which 
is due to a difference in the number of layers of cell tissue from which 
they originate: the calyptra is elongated below the operculum, cucullate or 
rarely campanulate in true Tetraplodon, while it is conical and covers only 
the top of the operculum in T. australis. 
Nor can our species be Haplodon, because of its exserted columella and 
geminate teeth with interior cavities. There remains then only the genus 
Splachnum, and with this it agrees in all the characteristics cited, as separa. 
ting it from the two other genera of the same sub-family. But if the descrip- 
tions of the stem structure of Splachnum found in literature be compared 
with the facts noted in studying the stem of our Tetraplodon there appear to 
be differences. The cross section of the stem in T. australis shows false 
leaf-traces, while in the case of Splachnum there are said to be true leaf, 
traces. But the information furnished by literature upon this point is not 
exhaustive and the generic difference between Splachnum and Tetra- 
plodon australis actually non-existant. Lorentz, who had studied the 
structure of the stem in the two Splachnums, S. sphaericum and S. luteum , 
says after describing it in 5 . sphaericum (Flora, 1867, p. 537): “We 
find this structure of the stem also in the following species of our genus, v 
i. e. S. luteum, “not, however, in Tayloria nor in Tetraplodon. It is per- 
haps not too bold to assume that this characteristic occurs also in other 
species of the genus and furnishes an excellent generical distinction from the 
other Splachnaceae.” This general conclusion made by him with reserva- 
tion, is reproduced without restriction by Limpricht. (Laubm. FI. Deutschl. 
Oesterr. u. d. Schweiz. (II. p. 164.). But if this is true in the species exam- 
ined by Lorenz, it is however incorrect in 5 . ampullaceum and S. vasculo- 
