The Present Position of Palaeozoic Botany. 



151 



br' 



fei 



ax 



Fis-. 



cimens now included under the name SphenophijUnm Dairsoni, appear 

 to belong- to two distinct species, one of which is in all probability 

 identical, as Zeiller believed, with the well known S. cuneifolium. 

 The fructifications are long-, cj'lindrical 

 cones (Fig. 1), consisting- of an axis bearing- 

 numerous verticils of bracts, w^hich are 

 connate in their lower part, forming a cup 

 or disc. The sporang-iophores spring from 

 the upper surface of the bract-whorl, near 

 its insertion on the axis; as a rule two of 

 them correspond to each bract. On each 

 sporang-iophore, which is traversed by a 

 vascular bundle connected with that of the 

 subtending bract, a single pendulous spo- 

 rangium is borne. This type of cone, with 

 some variations in detail, appears to have 

 heen common to a considerable number of 

 species. 



In BoivmanUes Piömeri^), from the Coal- 

 Measures of Poland, described by Solms- 

 Laubach (1895), the g-eneral relation bet- 

 ween the sterile and fertile appendages is 

 similar to that in Sphenopliyllum Dawsoni, 

 but here the sporangiophore is expanded 

 at the top into a peltate lamina on which 

 two sporangia are borne. In detail there 



are many points of agreement with the S. Dcnvsoni type, but in Boic- 

 maniies Römen the high development of the sporangiophores and their 

 bisporangiate character show that these organs are definite fertile 

 lobes of the sporophj^ll, a conclusion which is less evident in the case 

 of the. monosporangiate forms. 



The newly discovered Splienophyllum fertile (Scott 1905) from the 

 Lower Coal-Measures of Lancashire, resembles JBowmcmites Bömeri in 

 having peltate, bisporangiate sporangiophores, but is peculiar in the 

 fact that both the dorsal and ventral lobes of the sporophylls are 

 fertile, the sterile bracts of the other species being here represented 

 by additional sporangiophores. The lobes of the sporophyll, whether 

 dorsal or ventral, divide in a palmate manner into several branches, 

 each of which constitutes a sporangiopliore (Fig. 2). The anatomy of 

 the axis is well known in this case, and leaves no doubt that this 

 curious fructification belonged to a true Sphenophjllum. 



\i The generic name Bowmanites was given by Binney to fructifications which 

 have proved to be Sphenophyllaceoiis. It may still be retained in cases where the 

 lack of vegetative characters forbids a definite reference to the genus Sphenoiihyllnm . 



1. Splienophyllum Daiv- 

 soni. Diagram of cone in lon- 

 gitudinal section, ax, axis; 

 br, bracts; sp, sporangiopho- 

 res ; sm, sporangia ; hr', whorl 

 of bracts in surface view. 



