50 NILSSONIA. 



Genus NILSSONIA, Brongniart. 

 [Ann. Sci. Nat. vol. iv. 1825. p. 200.] 



In 1820 Nilsson l described and figured certain plant remains 

 from Hor, a small village north of Lund in Scania, and regarded 

 them as probably fern fronds, but he made no attempt to define 

 them specifically. In 1825 Brongniart refigured and described 

 some of Nilsson's specimens under the following specific names : 

 Nilssonia elongata, N. brevis, N. (?) eequalis, Pterophyllum majus, 

 and P. minus. It was on one of Nilsson's specimens that 

 Brongniart founded his genus Nilssonia, and also Pterophyllum ; 

 the two Hor species referred by Brongniart to this latter genus 

 have since been transferred by Nathorst 2 to Schimper's genus 

 Anomozamites. We have the first complete diagnosis of Nilssonia 

 in the Prodrome? where it is thus defined : " Feuilles pinnees ; 

 pinnules rapprochees, oblongues, plus ou moins alongees, 

 arrondies au sommet, adherentes au rachis par toute la largeur 

 de leur base, a nervures paralleles dont quelques-unes sont 

 beaucoup plus marquees." In his later work, 4 Brongniart retains 

 this name and speaks of Nilssonia as closely allied to Pterophyllum. 

 Miquel 5 substituted a new generic term, Hisingera, for some of 

 the species of Nilssonia, and as an example of the new genus he 

 cites Cycadites Brongniarti, Mant. Gb'ppert 6 accepts Brongniart's 

 genus in its wide sense, and does not suggest the institution of 

 any sub-genera. In 1856 Bornemann adopted the following 

 definition of Nilssonia:' 1 "Frondes coriacese, pinnatse, vernatione 

 circinatse, foliola contigua continue tota latitudine inserta, patentia, 

 abbreviata, basi passim cohaerentia, apice obtusa vel truncata, 

 nervis parallelis arcuatis apice confluentibus nonnullis validi- 

 oribus." This writer points out the difficulty of recognizing the 



1 Nilsson, p. 108. 



2 (A. 1), Flor. Bjuf. p. 66. 



3 p. 95. 



4 (A. 4), Tableau, p. 63. 

 6 (1), p. 61. 



6 (1), P- 139. 



7 Bornemann, p. 58. 



