224 



DK J. M. MACFARLANE ON THE 



/. Dianthus 

 alpinus. 



.'. Dianthus 

 Grievei. 



.'. Dianthus 

 barbatu6. 



the base ten in 1, thirteen in 8, and sixteen in 3 ; at the leaf middle fourteen in 1, seventeen 

 in 2, twenty in 3 ; and near the apex forty-eight in 1, fifty-two in 0, and fifty-five in 3. 



The epidermal leucoplasts figured in Plate IV. figs. 10-12, are as striking in the leaf as 

 in the stem, but in the hybrid they vary from 2 5 to 3*5 though inclining to the seed 

 parent. 



When leaves are macerated, and examined on surface view, it is seen that in 1 the 

 crystals are disposed very irregularly in the leaf, are not specially massed round the 

 vascular bundles, are nearly uniform in size, and are large in comparison with the size of 

 the leaf. In 2 many occur in the mesophyll, but a decidedly greater aggregation occurs 

 round the vascular bundles, which in places may seem almost coated with them ; they 

 also vary greatly in size. In 3 the vascular bundles are closely encircled in many places 

 by them, but large forms are frequent in the mesophyll. I counted the numbers in several 

 corresponding areas of the three, and found 40 in 1, 83 in 2, and 135 in 3. 



Sepals. — The gamosepalous calyx in 1 is obconate, dark purple-red in the upper part 

 of the tube, but green beneath the bracts, with broad sepaline teeth. In % it is tubular 

 obconate. pale crimson-red shading below into dark green and then into light green, and 

 with pointed sepaline teeth. In 3 it is tubular, and rich green above shading into light 

 green below, and this again into membranous white, while the sepaline teeth are acuminate- 

 ciliate. In 1 the outer calyx surface shows faint irregular ridges ; in 3 the ridges are 

 very evident, and there are nine to each sepal ; in 2 the development is intermediate. 



On transverse section 1 shows a series of nearly or quite equal fibro-vascular bundles 

 beneath and opposite each sepaline groove, the fibre or stereome part of each being very 

 large. In 3, three to four shallow grooves intervene between each pair of deep grooves, and 

 bundles of corresponding size lie opposite these. In the hybrid the grooves and bundles 

 are slightly nearer to the seed parent in type than exactly intermediate. The mesophyll 

 of the sepals agrees in fundamental arrangement with that of the vegetative leaf, as do 

 the crystals found in it. 



Petals. — The comparative naked-eye appearances of these are set forth in Plate IV. figs. 

 13, a, b, c. A little above the junction of claw with blade in 1 there are long unicellular 

 hairs, the longest being 2 mm. ; in 3 the hairs are absent, while in £ the longest is \\ mm. 

 I have frequently measured these from different flowers, and the hybrid appears always to 

 have a preponderating bias towards the seed parent. Above these hairs every epidermal 

 cell is enlarged into a little up-directed papilla, which is smallest in 1, largest and thickest 

 in 3, intermediate in 2. 



Stamens. — As compared with the parents, these are short and feeble in the hybrid. 

 The anthers are small, and have not a plump look. The good pollen grains of 1 are 10 /x 

 across; but as grown in the Edinburgh Garden many are small, shrivelled, and manifestly 

 impotent, this being probably due to change of habitat. The plants, however, from which 

 these were taken annually produce abundance of good seed, so that sufficient good pollen 

 must be formed to fertilise the ovules. The pollen grains of 3 are 14 m in diameter, and 

 there is seldom an abortive one amongst them. Those of the hybrid are bad in all 



