COAL PLANTS. 



COAL PLANTS. 



34 



Odontopterit has leaves like the last, but its leaflets adhere to the 

 stalk by their whole base ; there is no midrib ; and the veins spring 

 aide by side at once from the base of the leaflet, passing onwards 

 towards the point. 



Odoalopttrit Brardii. 



Sphenopterii has twice or thrice pinnatifid leaves ; the leaflets are 

 narrowest at the base, and the veins generally arranged as if they 

 radiated from the base ; the leaflets are more frequently wedge-shaped 

 than any other figure. 



Sphenopteris arteniuUrfolia, magnified. 



Lonchopterit hag the leaves several times pinnatifid, and the leaflets 

 more or less united to one another at the base ; there is a distinct 

 midrib, and the veins are reticulated. 



51 



Lonchopterit Jlricii. 



Cyclopterii has the leaves simple, and either altogether undivided 

 r unly lobed at the margin ; they are more or less orbicular, and are 

 t.li.'.l with veins radiating from the base ; there is no midrib. Speci- 

 mens of this genus are common in ironstone nodules. 



HAT. HWT. DIV. VOL. II. 



Cyclopttris orliculaHs. 



&:hizopteri3 is like the last, except that the leaf is deeply divided 

 into numerous unequal segments, which are usually lobed and taper- 

 pointed. 



Under the name of Caiilopterw are comprehended all the kinds of 

 stems of tree-ferns. They are found in the form of short, round, or 

 compressed truncheons, marked externally by oblong scars of consi- 

 derable size, much wider than the spaces that separate them, and 

 having their surface irregularly interrupted by projecting points. 

 Such appearances are owing to the manner in which the woody parts 

 of the leaf when fresh were connected with the stem. The fragments 

 to which this name is given no doubt belong to leaves bearing other 

 names ; but as the stems and leaves are never found united, it is 

 impossible to identify them. Remains of tree-fern stems are of such 

 rare occurrence that up to the present time not more than two or 

 three specimens have been found in the rich coal-fields of Great 

 Britain. 



Dr. Joseph Hooker observes, with regard to the species of fossil 

 ferns, that the characters on which many of them have been 

 founded are quite insufficient to prove them distinct. He shows that 

 amongst recent ferns the presence of the fructification is alone suffi- 

 cient to show the identity of forms that, according to the method 

 of procedure amongst fossil ferns, would be widely distinct. 



3. Coal Planlt with which no existing Analogy has been satisfactorily 



traced. 



Calamita are fossils found in short, jointed, cylindrical, or com- 

 pressed fragments, with channels furrowed in their sides, and some- 

 times partially surrounded by a bituminous coating, the remains of a 

 cortical integument. 



Ciiltiinitcs drtbius. 



They were originally hollow, but the cavity is usually filled up with 

 the substance into which they themselves are converted. They were 

 separable at their articulations, and, when broken across at that part, 

 show a number of stria- originating in the furrows of the sides, and 

 turning inwards towards the centre of the stem, which however they 

 do not reach. It is not known whether this structure was connected 

 with an imperfect diaphragm stretched across the hollow of the 

 stem at each joint, or whether it merely represents the ends of woody 

 plates of which the solid part of the stem was composed. Their 



D 



