496 Mr. E. Kidston on a new Species o/" Psllotites. 



thorn-like growths are apparent, distant from each otlier 

 9-12 millim. Towards the upper part of this brauchlet tliey 

 become less distant from each other. These projections 

 a])pear as round-pointed flat tliorns, arising from the stem at 

 almost right angles, and forming a single vertical row. 

 On all the branchlets they occupy a similar side. The stems 

 are strongly marked with irregular vertical striations or 

 ridges (c?, enlarged). 



I have placed this plant in Psilotites as employed by Gold- 

 enberg *. The stems of Goldenberg's species divide dichoto- 

 mously ; but the dichotomies in his specimens are often very 

 unequally developed ; hence some of the branchlets assume 

 the appearance of a lateral ramification. 



In the present example, as the attachment of the three 

 branchlets to their parent stem is not shown, and as an un- 

 equally-developed dichotomy might produce three branches 

 holding the same relation to each other as those of Psilotites 

 unilateralis f, I think that this fossil may, at all events for 

 the present, be conveniently placed in the genus Psilotites^ 

 whose true affinities, how^ever, to the recent Psilotum are 

 somewhat problematical. 



What the real significance of these thorn-like protuberances 

 is, whether rudimentary leaves or abortive branches, I am not 

 in a position to decide. 



The general appearance of the branchlets of Psilotites uni- 

 lateralis reminds one much of Dawson's genus Psilophyton ; 

 but the curious arrangement and form of the thorn-like pro- 

 tuberances point to greater affinities with the genus Psilotites^ 

 as employed by Goldenberg. 



Till more complete examples of this interesting plant be 

 discovered its true affinities cannot be definitely decided. 



The only specimen I have seen is that figured, which was 

 found by Mr. Walter Burns in 1884, who sent it to Mr. John 

 Young, F.G.S., Hunterian Museum, Glasgow University, by 

 whom it was communicated to me for examination. 



Horizon. Coal-measures. 



Locality. Baillieston Pits, Lanarkshire. 



* * Flora Saraspontaua fossilis : Die Pflanzenversteinerungen des Stein- 

 kohlengebirges vou Saarbriickeu,' Heft i. p. 13 (1855). 



t A similar apparent lateral raniificatiou, arising from unequal di- 

 cliotomy, occurs in the fronds of most ferns. 



