VOL. XVI. NO. 2 — BOTANICAL GAZETTE — FEB.. 1891 



Notes on the apical growth in the roots of Osmunda and 



Botrychium. 



DOUGLAS HOUGHTON CAMPBELL. 



(with plate v.) 



With the rapid advance in histological methods, it has now 

 become possible to study with the utmost exactness the de- 

 velopment of the most delicate plant tissues, and in conse- 

 quence a new impulse has been given to the investigation of 

 the histogeny of the higher plants, with a view to elucidating 



their affinities. 



Naturally the Pteridophytes have been among the most 

 frequently investigated forms, and my purpose here is to put 

 in brief form the results of some observations on the growing 

 points of the roots of Osmunda and Botrychium, which may 

 serve to supplement the more extended researches of other 



authors on the ferns. 



Of the genus Osmunda, O. regalis has been exhaustively 

 studied by Bower 1 , but our other native species, O. cinnamo- 

 mea, and especially O. Claytoniana are, so far as their his- 

 tology is concerned, almost unknown. 



These species, therefore, were chosen for the examination 

 of the roots. Of the genus Botrychium, B. ternatum, and B. 



Virginianum were used. 



The roots were fixed with a 1 per cent aqueous solution of 

 chromic acid, or in some cases with Flemming s chrom-osmic- 

 acetic-acid mixture, but the former was found to give the best 

 results. After thoroughly washing, to remove all traces of 

 the acid, and then dehydrating, the specimens were brought 

 gradually through turpentine and then imbedded in paraffin 

 and sectioned on a Minot microtome. Various stains were 

 tried, but by far the most satisfactory was a solution of Bis- 

 marck-brown in TO per cent, alcohol. The specimens were 

 stained on the slide with this mixture, which stains the young 

 cell-walls strongly, and renders the study of the earlier cell- 

 divisions an easy matter. 



1 Bower: The comparative examination of the meristems of ferns as a phy- 

 logenetic study. Annals of Botany, vol. Hi, no. 9, Aug. 1889. 





