'M')4: Mondrous Floiwr of Iris Pseudacorus. 



y = Cotyledon which, has goue on to development as a leaf 

 essentially similar in character to the ordinary foliage-leaves, and 

 has become elevated above its fellow by formation of an intemode. 



2 = Main axis. 



X axb = Axillary bud of smalltr cotyledon. 



y axb = Axillary bud of larger cotyledon. 



y acb = Accessory bud developed between the last and the base of 

 the cotyledon. 



On the Estivation of the Floral Envelopes in Helianthemum 

 vulgare. By Professor Dickson. 



(Read 13th July 1882.) 



It has long been known tlmt the three large sepals and 

 the petals in this plant are convolute in the opposite 

 directions. It does not, however, appear to have been 

 previously noticed that the contortion or convolution of 

 each of these floral envelopes is alternately to right and to 

 left in the flowers along the false axis of the scorpioid 

 cyme. This fact is of considerable interest in connectiou 

 with the theory of the scorpioid arrangement as the result 

 of lieterodromy of the leaf-spirals in the successive axes of 

 which this cyme is made up ; a theory of the truth of 

 which still more conclusive evidence was afforded by the 

 late Professor Hofmeister, who showed that in the flowers 

 of Boraginacece, such as Echium and Cerinthe, the calycine 

 segments of tlie sticcessive flowers on the cyme form an 

 alternately right- and left-handed quincuncial arrangement. 



On a Monstrosity in the Flower of Iris Pseudacorus. 

 By Professor Dickson. 



(Read 13tli July 1882.) 



In a specimen gathered recently at an excursion to 

 Longniddry the outer perianth segments were normal ; but 

 of the inner ones only two were normal, whilst the third 

 one was nearly completely metamorphosed into a stamen 

 with distinctly formed filament and anther containing 

 pollen, the extremity of the anther ending in a petaloid 

 expansion. And in each of the three unopened flowers of 

 the same inflorescence there was, in like manner, a fourth 

 stamen of somewhat smaller size than the three normal 



