XXX] TRIGONOCARPUS 117 



satisfactory evidence as to the nature of the reproductive 

 organs. 



Lotsy 1 has expressed the opinion that the bodies attached 

 to Neuropteris pinnae described by Kids ton and other authors as 

 seeds may possibly be vegetative buds, but if this were the case 

 one would expect to find some evidence of the bud-nature in 

 some at least of the specimens that have already been found. 



It would seem that the microsporophylls of Neuropteris were 

 constructed on different plans, some being of the type described 

 by Zeiller and other observers as Potoniea, while others bore 

 sporangia on pinnae without any accompanying laminae ; but our 

 knowledge of the latter form represented by Kidston's specimen 

 of Neuropteris heterophylla (fig. 421, D) is very incomplete. On 

 the other hand the seeds appear to have been characterised by 

 features suggesting a close affinity to Trigonocarpus and pointing 

 to membership of the same family. 



Alethopteris. 



Although no specimens have been discovered showing actual 

 connexion between fronds and seeds, it is practically certain 

 that Alethopteris leaves, or at least some species of the genus, 

 bore seeds of the Trigonocarpus type. The association of Trigono- 

 carpus Parkinson* with Alethopteris lonchitica is too frequent to 

 be fortuitous and there is further evidence afforded by certain 

 anatomical resemblances. In France other species of Alethopteris, 

 e.g. Alethopteris Serlii and A. Grandini, occur in association with 

 Pachytesta z , a large seed similar to Trigonocarpus, and Trigono- 

 carpus is found in the Pas-de-Calais coal-field with Alethopteris 

 Serlii. 



TRIGONOCARPUS. Brongmart. 



The generic name Trigonocarpum was instituted by Brongniart 

 in 1828 3 for ovoid longitudinally ribbed 'fruits' from Upper 

 Carboniferous strata, the type-species being named T. Parkinsoni. 

 The generic name is often altered to Trigonocarpon : Williamson 4 , 



1 Lotsy (09) p. 72. 2 Qrand'Eury (04); (04) B. 



3 Brongniart (28) A. p. 137. 



4 Williamson ( 77 )B. ; Scott andMaslen(07) p. 90 (footnote) also refer to Trigono- 

 carpon as having been used by Brongniart in 1849. 



