XXIX] LAGENOSPERMUM 65 



calated here as the habit of the seed-bearing axes supplies a 

 probable key to the habit of the fertile fronds of Lyginopteris. The 

 type-specimens were collected by Mr Sinclair from the Lower 

 Coal Measures of Ayrshire, Scotland, and recorded by Kidston as 

 Lagenostoma sp. : they were afterwards named by him in manu- 

 script L. Sindairi and handed to Dr Arber for description. The 

 seeds are elliptical-oblong, 4-5-5 x 1-5-3 mm., radially symmetrical 

 and enclosed by a loose envelope which is longitudinally ribbed and 

 divided distally into several linear-lanceolate lobes (fig. 408, A, A'). 

 This covering, though much longer than the cupule of Lagenostoma 

 Lornaxi, is probably a homologous structure. The most interesting 

 point is the attachment of the seeds to slender branches of a 

 compound axis (fig. 408, A). It is probable that the seeds were 

 borne on a frond characterised by the reduction or complete 

 abortion of the sterile lamina or perhaps, as in the recent Fern 

 Thyrsopteris elegans 1 , some of the pinnae of a large compound 

 frond were fertile. It is worthy of note that Arber recognised 

 pinnules of Sphenopteris obtusiloba 2 in association with L. Sindairi,. 

 a fact, as he says, in itself of no value but which acquires signifi- 

 cance in view of the discovery by Carpentier 3 of cupules in close 

 proximity to the same species of frond. Specimens described by 

 Dr Stopes from Westphalian rocks of New Brunswick as Pteri- 

 spermostrobus bifurcatus* bear a close resemblance to L. Sindairi. 



Lagenospermum oblongum (Kidston). 



The species recently described by Dr Kidston 5 as Lagenostoma 

 oblonga from the South Staffordshire coal-field appears to be 

 closely allied to Arber's L. Sindairi: it is represented by pairs 

 of seeds borne at the ends of forked branchlets : the seed is 2-5 mm. 

 long by 1-5 mm. broad and is surrounded by a longer oblong 

 cupule divided distally into 6 free lobes. 



A larger type of seed, 3 cm. long and 2-5 cm. broad, is described 

 by Kidston 6 from the same coal-field as Lagenostoma^ urceolaris. 

 A characteristic feature is the truncate apex surrounded by a 

 prominent canopy formed of the expanded apical free portion of 



1 Vol. ii. pp. 294, 295. 2 Vol. n. p. 529, fig. 352. 



3 Carpentier (11) p. 3. 4 See page 66. 



5 Kidston (14) p. 160, PI. vn. figs. 1, 2. 



6 Ibid. p. 161, PL xvi. figs. 9, 10. 



s. IT 5 



