8 



PALEOZOIC FOSSIL SPORES 



found in organic union. Whatever attitude 

 may be adopted, it is of fundamental im- 

 portance for later consistent application 

 of taxonomic principles. For this reason it 

 seems desirable to state views applicable 

 to the present work. 



The few unusually complete specimens 

 are highly significant in showing beyond 

 question that certain isolated organs at a 

 particular locality and stratigraphic level 

 possess identity of relationship.* This 

 identity must become more dubious, in 

 the case of isolated parts, the further they 

 are removed geographically and strati- 

 graphically from the site of proved union. 

 Stratigraphic discrepancy is most likely to 

 cast doubt on specific identity ; geographic 

 discrepancy may be cause for qualification 

 of the presumed relationship in varying 

 degrees of subspecific magnitude (there is 

 no basis for assuming that geographic 

 races were less in evidence in the past than 

 they are at present). If evolution is a 

 more or less continuous attribute of life 

 processes, over a period of time significant 

 alterations in some of the many heritable 

 characteristics are bound to occur. An in- 

 dividual alteration, although of specific 

 significance, will not necessarily involve 

 phenotypic expression in the majority of 

 the other characteristics of the race. For 

 this reason it is inaccurate to postulate the 

 continued specific coordination of an ex- 

 tensive garniture of biocharacters over a 

 period of time, without correspondingly 

 detailed knowledge which proves that the 

 characteristics dealt with were not subject 

 to mutative or other evolutionary processes 

 during that time interval. This detailed in- 

 formation is most readily determined for 

 a restricted group of biocharacters which 

 can be observed on common specimens. 

 Practical reasons dictate that emphasis in 

 systematic treatment be placed on the more 

 common types of fossils rather than on 

 those which show unusual preservation. 



Demonstrated connections between 

 spore forms and types of fructifications 

 prove readily that some of the adjacent 

 isolated specimens of either category are 

 also conspecific. The diverse taxonomic 

 groups, diagnosed on the basis of typical 

 isolated specimens are proved, therefore, 



* No plant, and certainly no single specimen, can have 

 more than one valid name. However, instances arise in 

 which it is difficult to determine which of two or more 

 names should actually be applied. In spite of this, syste- 

 matic procedure demands that an author follow some 

 consistent usage. 



to have coordinate significance through a 

 part of their geologic life as species. Dur- 

 ing this particular period, identity of re- 

 lationship must exist. But the most perti- 

 nent fact encountered in systematic treat- 

 ment of the common isolated forms, is that 

 this period of actual synonymy can scarce- 

 ly ever be defined. As a general thing, due 

 to discontinuity in the fossil record, it is 

 impossible to establish the points at which 

 old characters became coordinated in a 

 new fashion or with other characteristics 

 new to the phyletic succession. 



Consequently these overlapping rela- 

 tionships do not lend themselves to taxo- 

 nomic expression within specific and gen- 

 eric nomenclatural categories. Groups of 

 suprageneric rank, which are less depend- 

 ent on type specimens for their proper 

 definition, may be better used in expressing 

 such relationships of generalized validity. 

 The present paper, however, does not deal 

 with groups of suprageneric taxonomic 

 status. 



4. Various criteria for determination 

 of synonymy have been used by paleobot- 

 anists. The practice we prefer is conserva- 

 tive to the extent that unless conspecific 

 relationship is proved for two nomencla- 

 tural types, both names are valid. As such, 

 they are available for any purpose of use- 

 ful nomenclature. There are a large num- 

 ber of "partial synonyms" among the 

 named species of fossil plants to which 

 these remarks apply. The word "synonym" 

 of course is an absolute term — "partial 

 synonyms" are not synonyms ; in most in- 

 stances the names serve useful purposes in 

 indicating groups of different circum- 

 scription. None of these names should be 

 lightly considered ; neither should a name 

 be used in unqualified application unless 

 its pertinence is evident. Evidences of 

 "partial synonymy" undoubtedly record 

 close natural relationship, but the names 

 should not be regarded as invalid unless 

 shown to be mutually inclusive. Lacking 

 this, they remain applicable to fossils con- 

 specific with their basic nomenclatural 

 types. For the research worker there are 

 advantages in this conservative view of 

 synonymy, as it tends to promote a more 

 precise differentiation of fossils. This 

 basically, is a fundamental reason for the 

 continued use of technical nomenclature, 

 necessary to progress in the study of fos- 

 sil plants. 



