428 



CONIFERALES INCERTAE SEDIS 



[CH. 



constitute the most striking feature of the genus: the cone-scales 

 (sporophylls) - are entire, elongate-lanceolate (fig. 800) with an 

 acuminate apex, and each bears 5 6 pairs 

 of seeds characterised by a cup-like basal 

 investment or cupule (fig. 800, C). The 

 sporophylls have a strongly developed keel 

 on the lower surface and a less distinct 

 median rib between the two rows of seeds 

 on the upper face (fig. 800, A, B). There 

 is no evidence to support the view that the 

 cone-scales are double 1 . Schenk 2 described 

 the cone-scales as bearing 10 12 seeds on 

 the edge and Saporta 3 believed the seeds 

 to be lobes of a seminiferous scale, each 

 lobe supporting one seed. Nathorst's in- 

 vestigation of Scanian material has thrown 

 a welcome light on the nature of the mega- 

 strobili as interpreted by previous authors. 

 The bodies described by Schenk as seeds 

 are projecting spherical casts of cup-like 

 organs which originally embraced the lower 

 portions of the seeds. The morphological 

 nature of the cupule cannot be determined, 

 but as Nathorst suggests it may correspond 

 to the epimatium 4 which partially encloses 

 the seeds of Dacrydium and other recent 

 Conifers. Nathorst compares the cone-scales of Palissya with those 

 of the genus Cunninghamia (fig. 684, K, p. 116) in which each sporo- 

 phyll bears three seeds on the adaxial side of a membranous out- 

 growth stretched across the scale. The resemblance would seem 

 to be closer than Nathorst suspects as the membrane in Cunning- 

 hamia does not arise as a continuous strip of tissue but as three 

 separate ligule-like pieces, one on the abaxial side of each seed. 



1 Solms-Laubach (91) A. p. 73. 



2 Schenk in Schimper and Schenk (90) A. p. 336. 



3 Saporta (84) p. 513. 



4 Seepage 118. 



B 



FIG. 800. Palissya spheno- 

 lepis. A, B, sporophyll 

 in surface-view and in 

 section. C, cupules of two 

 seeds. (After Nathorst.) 



