130 VASCULAR CRYPTOGAMS 



of sporophylls without any intermediate barren whorls ; the separate 

 leaves are often saccate, the narrow^ apices ascending and covering in an 

 imbricate fashion the bases of the next upper whorl. The position of the 

 sporanges differs materially from that of the other Equisetaceae. They 

 are comparatively large bodies, lenticular, from i to 2*5 mm. in diameter, 

 solitary and sessile in the saccate hollow on the upper surface of the 

 base of the sporophyll. The solid remains have not yet been found in 

 a sufficiently perfect condition for the structure of the spores to be 

 determined with any degree of certainty, but no sufficient evidence of 

 heterospory has been presented. 



From the form and position of the sporanges the Sphenophyllese are 

 placed by some writers under Selaginellaceae ; but in the general appear- 

 ance and structure of the vegetative organs they approach so nearly to 

 the Calamariese that it seems best at present to place them here until 

 we are better acquainted with the details of the fructification. Stur has 

 recently described and figured specimens with leaves of Asterophyllites 

 at the base, Sphenophyllum-leaves higher up, and terminating in a fructi- 

 fication. 



Literature of Fossil Vascular Cryptogams. 



Sternberg — Flora der Vorwelt, 1821-1838. 



Brongniart— Hist, des Vegetaux Fossiles, 1820-1840; (Sigillaria, Stigmaria, and 



Lepidodendron) Arch. Mus. d'Hist. Nat., 1839. 

 Lindley and Hutton — Fossil Flora of Great Britain, 1833-1837. 

 Witham — Internal Structure of Fossil Vegetables, 1833. 



Goppert— Systema Filicum Fossilium, 1826 ; Gattungen der fossilen Pflanzen, 1841. 

 Unger — Genera et Species Plantarum Fossilium, 1840. 



Corda — Beitr. zur Flora der Vorwelt, 1845. 



Hooker^ Vegetation of Carboniferous Period, in Mem. Geol. Survey, 1847. 



Brown — Triptosporites, in Linn. Soc. Trans., 1 85 1. 



Geinitz — Steinkohlenformation in Sachsen, 1855. 



Ludwig — Calamiten-Friichte Palaeontographia, 186 1. 



Goldenberg — Flora Saraepontana, 1862. 



Binney — Fossil Carboniferous Plants, Palceont. Soc, 1 868-1 875. 



Schimper — Paleontologie vegetale, 1 869- 1 874. 



Weiss — Fossile Flora der Steinkohlenformation, &c., 1869 ; Beitr. zur fossilen Flora, 

 T876-1884. 



Carruthers — (Ulodendron and Bothrodendron) Monthly Micr, Journ., 1870; (Lycopo- 

 diaceae) 1869; (Calamites) Seemann's Journ. Bot., 1867. 



Dawson— Fossil Plants of Upper Silurian and Devonian of Canada, 1871-18S2 ; 

 Geological Hist, of Plants, 1888. 



De Saporta — Paleontologie Francaise, 1873. 



Grand'Eury— Flora Carbonifere du Dpt. de la Loire, &c., 1877. 



