142 THE JOURNAL OF BOTANY 



would solve a problem which has so far baffled all attempts at solu- 

 tion, and also throw a flood of light on the mnge of variation in the 

 offspring of such crosses. It should be borne in mind that the seeds 

 must be sown in pots containing the soil in which the parents 

 originally grew, as the}?" will not germinate unless the microscopic 

 fungus (rhizoctoiiia) which infects the roots of orchids is present 

 (see Prof. F. E. Weiss's paper on Seeds and Seedlings of Orchids 

 in Proc. Manchester Microsc. Soc. 1917). The simplest way is 

 to grow prcetermissa and macidafa in pots, taking up with them the 

 ball of earth in which they grow, and to sow the seeds on the surface 

 of the pots. I should be glad to hear from any readers the results of 

 their investigations, addressed to me c/o Messrs. Cox & Co., 16 Charing 

 Cross, London, S.W. 1. No specimens, however, should be sent till 

 my actual address at the time has been ascertained by a postcard to 

 me at the above address. 



NOTES ON BRAITHWAITE'S SPHAGNACE^ EXSICCATE.. 

 By J. A. WiiELDON. 



Dr. Braithwaite published his great work on The Sphagnacece 

 or Pent Mosses of Europe and America in 1880 : his SpliagnacecE 

 BritanniccB ExsiccafcB appears to have been issued whilst preparing 

 this work. Through the kindness of Mr. H. Beesley of Preston, I 

 have been allowed to examine a copy of the latter which belonged to 

 the late M. B. Slater of Malton. This, on the dedicatory page, is 

 dated in the Doctor's handwriting April 1877, just a month prior to 

 the issue of the circular announcing the publication of his work on 

 the Sphac/nacecB. I am unacquainted with the whereabouts of the 

 other copies, nor do I know whether the specimens in them are from 

 identical gatherings ; but I suspect this is not always so, as in a few 

 instances I find my determinations do not accord with other published 

 ones. A very small proportion of the specimens aj^pears to have been 

 collected by Braithwaite himself, the principal contributors being 

 Messrs. J. M. Barnes, S. Anderson, W. Curnow, Gr. Stabler, J. Sim, 

 and J. E. Bagnall. Some of the examples are too scanty, and, being 

 gummed down, could not be examined with the completeness that is 

 so desirable with these difficult subjects. In some cases, however, 

 loose material in envelopes accompanied the mounted plants. 



It was interesting to find in the collection a confirmation of 

 Mr. Bellerby's record of Sphagnum havaricnm Warnst. His plant 

 was named by Warnstorf, but the specimen was not returned, and 

 therefore no example was existent in our collections. The plant of 

 Anderson, which I refer to this species, was collected in the same 

 locality as Mr. Bellerby's, viz. Goathlands, Yorkshire. Some of the 

 pages of the volume are blank, having been reserved for varieties 

 which were apparently unobtainable. These, and a few foreign 

 species, or others which do not call for comment, account for the 

 missing numbers in the following list, in which the specimens have 

 been named in accordance with my Synopsis of the European 

 Sphagna published by the Moss Exchange Club. 



