BR. M. T. MASTERS OS A DOUBLK-rLOWKREB ORCUTS. 349 



But in another genus belonging to the same family, namely the 

 Davilla, the stem twines indifferently from left to right or from 

 right to left ; and I once saw a shoot, ascending a tree about five 

 inches in diameter, reverse its course in the same manner as so 

 -frequently occurs with Loasa. Although individuals, as we have 

 just seen, in some few cases twine in opposite directions, yet you 

 say that you have not as yet met with any case of two species in 

 the same genus twining in opposite directions, and you are able 

 to give only two cases of species within the same natural order 

 thus twining. But a Mikania growing here twines from right to 

 left, Mhilst the Mikania scandens described by you twines in an 

 opposite direction ; and I believe that there are species of Dios- 

 corea which twine in opposite directions. Lastly, with respect to 

 the thickness of the support which can bo ascended b}' spirally 

 twining plants, ,1 have lately seen a trunk about five feet in 

 circumference which was thus ascended by a plant apparently 

 belonging to the Menispermaeea\ 



On a Double-flowered Variety of Orcliis mascula. 

 By Maxwell T. Mas^/ers, M.D., F.l^S. 



[Eead Dec. 7, 1805.] 



[Plates X. & XI.] 



Ik May last, Dr. Moore, of Gkisnevin, laid before the Eoyal 

 Dublin Society flowers of this curious Orcliid, gathered at the 

 Bridge of Allan by Dr. Patterson, and subsequently was good 

 enough to forward the specimens to me for more complete exami- 

 nation and description. Dr. Moore's brief account may be found 

 in the Proceedings of the above-named Society (May 15, 18G5) ; 

 but, as my interpretation of these flowers diff'ers somewhat from 

 that given by my friend, I think it right to reproduce his remarks 

 in this place before proceeding to give the results of my own 

 examination. 



"The flowers," writes Dr. Moore, "are reversed on the axis 

 which bears them, the labellum being next the axis in place of the 

 sepals being uppermost^ which is the normal state of the flower. 

 Tiie changes of the parts are very curious and interesting. On 

 the sides of the labellum are two smaller labella with short spurs ; 

 and in the axils of these, other flowers spring, thus rendering the 

 morphology axillary. These secondary florets have, again, rudi- 

 mentary florets in the axils of their changed labella ; there is nu 



