FLORIN: SYSTEMATICS OF THE GYMNOSPERMS 365 



petiolate, and perisporangiate sporophyll, and the dorsiventral, hyposporangiate 

 form advanced. According to a third view (Doyle and O'Leary, Zimmermann, 

 1930, Florin), the microsporophylls originated from a radial sporangial truss 

 with terminal, erect sporangia, the laminate sporophyll represents a derived 

 condition, and the peltate perisporangiate sporophyll is an intermediate stage, 

 but has probably never occurred in the true conifers. Sporophylls with several 

 free sporangia and a well-developed vascular bundle system are held to be more 

 primitive than those with few sporangia fused to the basal portion of the sporo- 

 phyll and a weak bundle system. Wilde believed that the simple male cone as 

 found today in most conifers is a single surviving terminal unit of a fertile 

 branch that was once compound like the female. The organization in Cephalo- 

 taxus appeared to Nozeran (1949a) to unite in a single individual different 

 stages of evolutionary development, viz., a successive reduction of the secondary 

 axis and a transfer of the reproductive function from the appendages of this 

 axis to those of the primary axis, which correspond to the normally axillant 

 bracts. Finally, Allen (1946a) found the generally accepted concept of a hypo- 

 dermal origin of the microsporangium open to doubt. 



Boureau (1949; cf. Gaussen, 1952) studied the alternate tracheary pitting in 

 coniferous secondary wood, and distinguished three main types, viz.: (1) the 

 primitive multiseriate type of paleozoic age {Dadoxylon) ; (2) the uniseriate 

 type, appearing in early mesozoic time, or still earlier, and sometimes resembling 

 the type of pitting of the Pinaceae; and (3) a late, overevolved multiseriate type, 

 still present in the living Araucariaceae. He is of the opinion that a pinaceous 

 evolutionary branch originated at the end of the paleozoic era. Several mesozoic 

 woods are intermediate between Dadoxylon and modern Pinaceae. The Gothan 

 school interpreted them as forerunners of the Pinaceae, showing traces of arau- 

 carian or cordaitean ancestry (Protopinaceae), while the Jeffrey school con- 

 sidered them primitive araucarians of pinaceous ancestry (Araucariopitya- 

 ceae). Bailey (1933) found similar combinations of characters in living conifers, 

 e.g., Cedrus and Keteleeria, and concluded that certain Protopinaceae fall within 

 the range of structural variability of living Abietoideae and others within the 

 range of variability of the Podocarpaceae, Taxodiaceae, and Cupressaceae. Bai- 

 ley and Faull (1934) stressed the point that the lack of information on the limits 

 of structural variability is the cause of the unsatisfactory classification of fossil 

 coniferous woods. Most anatomical features utilized for diagnostic purposes — 

 even such as the pitting of rays and of wood parenchyma, and the contiguity 

 and alternation of tracheary pitting — vary in different trees, and not least in 

 different parts of a single tree. Similar studies were later carried out, particu- 

 larly by Bannan (1941a, 1941b, 1942, 1944, 1952), on various Pinaceae and Cu- 

 pressaceae. Krausel (1949b) was aware that the investigation of the wood struc- 

 ture in recent conifers could not be regarded as completed and that the value of 

 certain structural features used for identifying and classifying woods was not 

 absolute. But there were no sufficient reasons for an attitude as sceptical as that 

 of Bailey. Krausel insisted on the unique position of the Protopinaceae as com- 

 bining araucarian features with characters of other conifers and often showing 

 a transitional tracheary pitting. He admitted, however, the impossibility of 

 solving the old problem of the relative geological age of the Araucariaceae and 

 the Pinaceae on the basis of wood structure alone. All that could be said was 



