404 Mr. R. Kidston on the Genus Pothocites, Paterson. 
XLII.—On the Affinities of the Genus Pothocites, Paterson. 
By Ropert Kipsron. 
PROBABLY no genus of Carboniferous fossil plants has created 
so much interest amongst botanists as Pothocites. 
The first specimen was described by Dr. R. Paterson in 
1840 *, and was regarded by him as a Monocotyledon “ either 
belonging to an extinct species of the genus Pothos, or to some 
extinct genus of plants closely related to it.” This view has 
generally been accepted by subsequent writers ’’f. 
The specimen remained unique until 1876, when Mr. R. 
Etheridge, Junr., described a second species, P. Paterson {. 
From an examination of both of these plants I have been 
led for some time to doubt their Monocotyledonous nature; and 
this view is now proved correct by a specimen collected by 
Mr. T. Stock from the cement-stone group of the calciferous 
sandstone series, Glencartholm, Eskdale. 
This specimen, which I provisionally name Pothocites cala- 
mitoides, is fully 7 inches long; of this the spike occupies 
about 534 inches; and it is, as far as 1 am aware, the first 
specimen in which this plant is shown up to its extremity. 
The spike contains eight segments; and the stem, which is 
jointed as in ordinary Calamites, shows three nodes. 
Leaves are given off from the nodal regions of the spike 
and stem. ‘The jointed nature of the stem is equally well 
shown in P. Patersont, Ether. 
The small projection from the side of the stem in Dr. Pater- 
son’s original specimen, previously supposed to be the origin 
of the spathe, is the remains of a branch which bore a similar 
spike, as an example shows two such spikes terminating the 
branches of a dichotomous stem. 
The so-called stellate “ perianth-segments”’ are probably 
the deflected segments of sporangia which have shed their 
spores, and their component parts do not spring from a 
central tubercle, as represented in Dr. Paterson’s enlarged 
sketch: what has been mistaken for the central column is 
merely a central depression ; and the appearance caused when 
these minute bodies are viewed with lateral illumination has 
probably led to this error. 
From the facts brought out by the recently found specimen 
and a careful reexamination of the original P. Grantoni, 
* Trans. Bot. Soc. Edin. vol. i, part 1 (1841). : 
+ Prof. Balfour, ‘Vegetable Paleontology ;’ Carruthers, Geol. Mag. 
vol. ix. (1872) ; Geikie, ‘ Text-book of Geology,’ 1882, p. 732. 
t Trans. Bot. Soc. Edin. vol. xii. pp. 151, 168 (1876). 
