I 



246 BOTANICAL GAZETTE [march 



stem strongly resembles that of Osmundites skidegatensis from the western 

 coast of Canada (Lower Cretaceous). 



In a second paper, Gwynxe-Vaughan 18 has described the effect of injury 

 on a narrow stele of Osmnnda regalis. Tracheids appear in the central region 

 of the stele. The author regards this as evidence of the stelar origin of the 

 pith in the Osmundaceae. The voluntary blindness of British anatomists as 

 regards medullary structures is an interesting phenomenon. They welcome 

 the small amount of evidence which can be brought forward for the stelar 

 origin of the pith, and close their eyes to the overwhelming evidence for its 

 derivation from the fundamental system of tissues. The equitable procedure 

 seems to give the same value to both kinds of evidence, and decides the ques- 

 tion on the quantitative basis. We may record here the regret that American 

 anatomists all feel for the untimely death of the junior author Gwynne- 

 Vaughan, whose published work is of such promise. An appreciative obituary 

 has recently been published by Scott in the Annals of Botany, — E. C. Jeffrey. 



Monomelic capsules in Bursa. — The reviewer has shown 19 that the tri- 

 angular capsule of Bursa bursa-pastoris is produced independently by two dis- 

 tinct Mendelian factors (dimery), and has expressed the view (1914) that this 

 is a derivative condition, the original form of this species probably having had 

 only one of these factors. A considerable number of wild plants have been 

 investigated, but as yet only one specimen has been found by the reviewer 

 which had but one of the capsule factors, this case being still unpublished. 

 Dahlgren 20 has investigated a plant of this species growing in the botanical 

 garden at Upsala, and secured from a cross with B. Heegeri (which lacks both 

 of the factors for inflation of the capsules) an F 2 progeny consisting of 71 B. 

 bursa-pastoris and 17 B. Heegeri. One of these F 2 plants produced in the F 3 

 16 plants having triangular capsules and 3 with turbinate capsules, thus show- 

 ing that without doubt the B. bursa-pastoris used in this cross had monomeric 

 capsules. There remains one important question which the author fails to 

 mention. As B. Heegeri has been widely distributed in botanical gardens, it 



1m 



Dahlgren were a derivative of an earlier, natural 



between B. bursa-pastoris and B. Heegeri, its possession of but one of the capsule 



18 Gwyxne-Vaughan, D. T., On a " mixed pith " in an anomalous stem of Osmund* 

 regalis. Ann. Botany 28:351-354. pi. 21. 1914. 



I0 Shull, G. H., Bursa bursa-pastoris and Bursa Heegeri: biotypes and hybrids. 

 Carnegie Inst. Washington Publ. no. 112. pp. 57. Washington. 1909. 



, Defective inheritance-ratios in Bursa hybrids. Verhandl. Naturf. Ver. 



Briinn49: 157-168. 1911. 



, Duplicate genes for capsule-form in Bursa bursa-pastoris. Zeitschr 



Ind. Abstam. u. Vererbungs. 12: 97-149. 1914. 



20 Dahlgren, K. V. Ossian. Ein Kreuzungsversuch mit Capsella Heegeri Solms 

 Svensk Botanisk Tidskrift 9:397-400. 1915. 



