718 DR K. KIDSTON. 



Lagenospermum Nathorst. 



1914. Lagenospermum, Nathorst, Foss. Flora d. Polarldnder, Erster Teil, Vierte Lief. : Nachtrage zur 



palaeozoischen Flora Spitzbergens, p. 29. 

 1914. Radiospermum, Arber {pars), Annals of Botany, vol. xxviii, p. 101. 



Description. — Seeds generally small, oval, elongate, or spindle-shaped, which are 

 characterised in being entirely surrounded by a cupule, the upper margin of which is 

 usually, if not always, divided into teeth. The cupule frequently shows ribbing, and 

 this appears to correspond with the number of the teeth possessed by the cupule, 

 which are frequently six. In some cases the cupules seem to be smooth, though a 

 little furrow may pass down the cupule in a line corresponding with the margins of 

 two neighbouring teeth. The seeds themselves appear in some cases to be ribbed 

 {Lagenospermum Kidstoni Arber, sp.), while in other cases they are smooth.* The 

 seeds may be borne on a compound branch system or terminate dichotomously 

 divided branchlets. 



Remarks. — The genus is altogether provisional and was formed for the reception 

 of seeds having a cupular structure, as in Lagenostoma Williamson, which was, 

 however, founded on specimens showing their internal organisation. Several cupulate 

 seeds, of which only the external form, and in some cases also the outline of the seed, 

 is known, have been placed by their describers in Williamson's genus ; but as no 

 knowledge is possessed of their internal organisation, Nathorst founded the genus 

 Lagenospermum for their reception. Some of these may prove to be true members 

 of the genus Lagenostoma Will., but as at present we are entirely ignorant of their 

 structure beyond the fact that they possess a cupule, they have no claim to be 

 included in a genus founded on clearly defined anatomical characters. 



The genus Lagenospermum has been intentionally made a very wide one, and its 

 essential character is the presence of a cupule. There can be little doubt that, if we 

 knew the organisation of the seeds included in it, it would most probably be found 

 that they represent more than one type ; but from our present imperfect knowledge 

 of their structure it is much better to include such cupulated seeds, which are only 

 known as incrustations or impressions, in a provisional, wide and comprehensive, 

 genus. 



In Lagenospermum Nathorst I would include the following British species : — 



1905. Lagenorioma Kidstoni, Arber, Proc. Roy. Soc. London, vol. B Ixxvi, p. 247, pi. i, fig. 1 ; pi. ii, 



figs. 1-6. 

 1905. Lagenostoma Sindairi, Kidston, MS. Arber, ibid., p. 251, pi. ii, figs. 7-11. 

 1914. Lagenostoma oblongum Kidston, Trans. Roy. Soc. Edin., vol. 1, p. 160, pi. vii, figs. 1, la, 2, 2a; 



text-fig. 8. 

 1914. Lagenostoma 1 urceolaris, Kidston, ibid., p. 161, pi. xvi, figs. 9, 9«, 10, 10a. 

 Lagenospermum parvulum, Kidston, n. sp. 



* Carpentiee, " Sur cpielques fructifications et inflorescences du Westphalien," h'cvue generate de botanique, 

 vol. xxiii, p. 1, pi. xii, figs. 1, 4, 1911. 



