476 REPORT OF THE CONFERENCE ON GENETICS. 
ON THE PHYLOGENY OF ORCHIDS. 
By Proressor Prirzer of Stuttgart. 
[Every msmber of the 1906 Conference will have grieved to hear of 
the death of Professor Pfitzer, which occurred soon after his return to 
Stuttgart. His amiability and the depth and extent of his learning were 
noticeable to all; and the botanical world—and the horticultural world 
on its more scientific side—has sustained an irreparable loss. 
The following paper which he had intended sending for the Conference 
Report was found upon his writing-table, and was very kindly forwarded 
by his executors, but unfortunately not in time to be placed in its proper 
position in the volume. If any errors are found in it they will doubtless 
be due to the intense difficulty of deciphering the writing, which is all in 
English, the Professor having been an expert linguist, added to his other 
rémarkable attainments.—EDIrTor. | 
It is always very dangerous to say anything about the phylogeny of a 
group of plants if there are no paleontological evidences about their 
ancestors. On the other hand, it can hardly be expected that these 
evidences will ever be found about orchids and their allied plants. 
Therefore we must either entirely forgo any approach to this question 
or we must try to solve it with the clear consciousness that our 
suggestions have but a very limited value. But if a man has been 
working for many years on one particular family of plants, it is natural 
that he should form some opinion on this question, so that perhaps it will 
be forgiven in Darwin’s country if I venture to communicate to this 
Conference some of my ideas on the phylogeny of orchids. 
Generally speaking, the order Scitamine@ is considered the nearest 
relation to the Orchidacee@, and they certainly stand very near to each 
other. It is, however, almost impossible to suppose that the orchids have 
been derived from Scitaminee@.* The outer whorl of the perianth, so 
remarkably developed in orchids, is large only in Musacee@, which are very 
dissimilar to orchids in all other respects; in the Zingiberacee, which 
would come nearer to this family, it is generally reduced to a short tube 
split on one side; and if we would derive orchids from Zingiberacee it 
would be necessary to suppose that the single leaves of the calyx of 
Zingiber had become free and large. Also the apparent similarity that 
both groups—setting aside the Cypripediee—have only one perfect stamen, 
is no real link between them, because the only stamen in orchids is the 
“unpair’”’ of the outer whorl, in Zingiberacee the “unpair”’ of the inner 
whorl, while the one developed in orchids is entirely wanting in Zingi- 
beracee. So the similarity in the diagram of the flower is only apparent ; 
both families may have been derived from one common ancestor, which 
varied in two different ways, and gave on the one side a progeny that 
* The Scitamimee include such genera as Canna, Hedychium, Maranta, Musa 
Zingiber.—Ep1Tor. , 
