60 Botanical Notes. 



VIII. Botanical Notes. 



Six-leaved Clover. — A specimen of six-leaved clover, possess- 

 ing some features of interest, was found in Mount Eoyal Park 

 by Miss Van Home, on June the 6th. Upon examination, the 

 leaflets appeared to be united to the petiole in two distinct groups 

 of three each. The petiole was also flattened and had a width 

 about twice that of its thickness, while a strongly defined 

 median furrow gave unmistakable evidence that the monstrosity 

 was developed by union of the two leaves in the bud throughout 

 the entire length of their petioles. Furthermore, it was found that 

 there was only one pair of stipules instead of two, or their 

 rudiments, as might have been expected ; but this pair, instead 

 of being lateral to the base, as in a normal petiole, were median 

 along the central furrow, or in other words, they represented the 

 survival of the two interior stipules along the line of union, and 

 the suppression of the external stipule in each petiole. 



D. P. P. 



Tension. — An interesting case of tension developed through 

 conjunctive growth, was observed during the month of May 

 in a large elm tree at Abbotsford, P.Q., on the land of Mr. Chas. 

 Gribb. It appears that, originally, the tree forked a short dis- 

 tance above ground, and the main limbs thus formed con- 

 tinued to grow at a slightly diverging angle. As the two struc- 

 tures mutually approached through co ntinued growth in diameter, 

 the bark of their inner faces came in contact, and caused a compres- 

 sion which finally arrested further increase in that direction, but 

 forced the new growth out laterally. Thus, in time, the two 

 trunks came to present a plano-convex section, separated at their 

 plane surfaces by the persistent bark. Through excessive lateral 

 growth, and the added influence of strong internal tension, the 

 now closely approximated lateral edges of the two limbs ruptured 

 their bark and affected a complete union, thereby enclosing the 

 original bark of the two, in a firm and constantly thickening 

 case of wood. The compression increased with growth, and finally 

 brought the two layers of bark into a high state of tension, which 

 was made quite conspicuous at the time the tree was cut. When 

 the first section was made the compound trunk was found to be 

 nearly square in outline, with the extreme length of the diagonals 

 98 c. m. and 85 c. m., while the line of internal fissure, which 



