including a new Arrangement of Phanerogamous Plants, 461 



is winged, this probably arises from the pressure of the bracts or 

 the dense growth of the catkin, as it frequently takes place in 

 the central flowers of Ulmus. As the wings are dorsal, the central 

 fruit could not stand with its carpels anterior and posterior, and 

 the two carpels of Alnus, which are not winged, having the same 

 position as in the two latei'al flowers of Betula, show the latter 

 to be in their true relation to the axU. 



Platanace^e. Platanus is always referred to as having an 

 ovary consisting of a single carpel, and if so, its position would 

 be variable in the greatest degree; but it is rather a question 

 whether it does not consist of several distinct carpels, as it is not 

 uncommon to meet with five or six arranged in a circle, the ven- 

 tral suture of each being towards the centre and the carpels in 

 close contact with each other, no sepals intei-vening. The car- 

 pels are however so irregular, that the attempt to ascertain 

 whether they are single or form part of a whorl has proved as 

 yet unsuccessful. 



EXPLANATION OF PLATES XIII. XIV. and XV. 



Plate XIII. 



*^* These diagrams are formed exclusively from nature, each of them 

 being taken from one specimen only of each plant. 



Fig. 1. A vertical view of the position of the fertile carpel in a branch of 

 Valeriana officinalis : — a, the stem from which the branch springs ; 



b, b, the first pair of ramuli. The axis between the second pair 



c, c, and the third pair d, d, being vertical is not represented. The 

 central bud of the branch is abortive at the third forking, and the 

 ramuU c, c, are abortive at their first forking. 



Fig. 2. Centranthus ruber : — a, the axis ; b, b, two opposite branches ; 

 c, a transverse section of an ovary. Two bracteae are represented 

 at the base of each ovary on one of the rami, and the cross indi- 

 cates the position of the spur of the corolla. This diagram repre- 

 sents the internal branch of each forking, as regularly suppressed 

 after the branch b has twice forked ; so that the branch, the sta- 

 men, and the fertile carpel are then all lateral and external, the 

 origin of the filament being on the same side of the flower as the 

 fertile carpel. This occasions the fertile cell to look at first sight 

 as if it were next the axis, but the flower, when both branches are 

 developed as between the first two forkings d, has its spur coming 

 forward between the two branches, the spur having then ob- 

 viously the same position and relations as the gibbous process in 

 Valeriana officinalis. 



Fig. 3. represents the mode of growth and the position of the carpel in the 

 ramifications of a branch of a Mirabilis : — a, the axis. 



F^g. 4. represents the variable position of the fertile carpel in the cyme of 

 Viburnum Opulus ; the carpels are, perhaps, more frequently pos- 

 terior than here represented, and more so in other species. 



Fig. 5. Brunonia australis. The diagram represents the mode of growth, 

 and (supposing the raphe to be next the placenta) the position of 

 the fertile carpel in two of the dense fasciculi forming the capi- 

 tulum : — a, the axis. 



