CH. XXVIl] TAENIOPTERIS 485 



balanced by the risk attending a grouping under one name of 

 plants which may agree only in unessential characters. The 

 practice of classifying fossil plants has been carried to excess. 

 Grouping together genera as a matter of convenience unavoidably 

 creates a prejudice in favour of actual relationship, which may 

 or may not exist. 



Taeniopteris. 



This generic name was instituted by Brongniart^ for simple 

 linear or broadly linear leaves with a prominent midrib from 

 which secondary veins, simple or dichotomously branched, are 

 given off at right angles or obliquely. The frond of the type- 

 species Taeniopteris vittata (fig. 332), characteristic of Jurassic 

 floras, was compared by Brongniart with the pinnules of Danaea 

 and Angiopteris. Among recent ferns the Taeniopteris form 

 of frond and venation is represented by Oleandra neriiformis, 

 Asplenium nidus, and many other species. Though usually 

 applied to fronds which there is good reason for regarding as 

 simple leaves, the generic designation Taeniopteris has been 

 extended to include pinnate fronds, e.g. the Upper Palaeozoic 

 species T. jejunata Grand'Eury, and T. Carnoti Ren. and Zeill. 

 (fig. 330, A). The compound fronds from the Lower Coal- 

 Measures of Missouri described by Dr White ^ as T. missouriensis 

 are characterised by decurrent and confluent Taeniopteroid 

 pinnules. In a later reference* to this plant White pertinently 

 adds, " perhaps it belongs more properly in A lethopteris." 



Leaves of the Taeniopteris type are described by several 

 authors as species of Oleandridium, Angiopteridium, Danaeites, 

 Marattia, and other genera. In such species of Taeniopteroid 

 leaves as have been dealt with in a former Chapter, the 

 occurrence of sori justifies the substitution of a name denoting 

 a close relationship to existing members of the Marattiaceae, 

 but in the absence of fertile specimens the provisional designa- 

 tion Taeniopteris should be retained. It is often difficult to 

 decide between Taeniopteris and Nilssonia as the more suitable 



» Brongniart (28) A. p. 61. ' White (93). 



J White (99) p. 143. 



