8 GYMNOSPERMS 



Gradually, it was found that the leaf, Sphenopteris, the petiole, 

 KacJiioplcris, and the root, Kaloxylon, also belonged here, and that 

 the sporangia, Crossothcca, were the microsporangia of the assem- 

 blage. What should the plant be called? Lyginodendron Lagenosto- 

 ma Sphenopteris Rachiopteris Kaloxylon Crossotheca? That is obvi- 

 ously too long and too burdensome and so the whole assemblage is 

 called Lyginopieris. 



In others, various parts have been found associated and the link- 

 ing-up process is going on, but in no case has the assembling been so 

 complete as in Lyginopieris. 



As long as only scattered parts are known, it is convenient to de- 

 scribe them under names which indicate the incompleteness. Such 

 names are called form genera: they should not be regarded as equal 

 in rank to the generic and specific names of living plants. 



Names of leaves in this group are likely to end in -pteris or -phyl- 

 lum, and so we have Neuropleris, Dictyopleris, Sphenopteris, Pecop- 

 teris, Titanophyllum, Sphcnophyllum, Pterophyllum, and others. 



Names of stems are likely to end in -dcndron (tree), or -xylon 

 (wood), e.g., Cycadoxylon, Dadoxylon, Dictyoxylon, Kaloxylon, Me- 

 galoxylon, Cladoxylon, Poroxylon, Araucarioxylon, Asteroxylon, Ly- 

 ginodendron, ScJiizodendron, and others. 



Names of seeds usually end in -spermum, -carpon, -carpus or -stoma, 

 e.g., N euros permum, Stc phano spermum, Cycadinocarpus, Cardiocar- 

 pon, Trigonocarpus, Lagenostoma, Conosloma, Physostoma, and others. 



A common ending for stamens or microsporangia is -theca, e.g., 

 Crossotheca, Codonotheca. 



Names for cones often end in -strohilus or -strobus, e.g., Anihostrob- 

 ilus, Androstrobus, Zamiostrobus, and others. 



DISTRIBUTION 



In describing either the geological or geographical distribution of 

 any extinct groups, it must be kept in mind that intensive work has 

 been done only in the university zone of the northern hemisphere. 

 In institutions of the southern hemisphere botanical work is still 

 confined, principally, to the taxonomy of living plants, a very natural 

 field, since the first thing, in a new country, should be to find out 

 what is there. Expeditions into the southern hemisphere and into 

 out-of-the-way parts of the northern hemisphere, while valuable, 



