790 



MACROSCOPIC AND MICROSCOPIC CHARACTERS OF PLANTS. 



In the hybrid the number of cortex layers, the angle 

 between the two ridges, and the outline are between those 

 of the tivo parents; the depth of the epidermis is identical 

 with that of I. coccinea; the diameters of the cortex cells 

 and of the largest vasa are larger than those of the 

 parents. 



Pieces of the epidermis at the base of the petiole under 

 the same magnification show the characteristics given in 

 Table J 9: 



Table J 9. — Cells, glands, and multicellular protuberances of 



epidermis at base of petiole. 

 I. coccinea: Cells 60 by 22m; glands 1 ; diameter of glands 34m; length 



of multicellular protuberances 144m- 

 /. quamoclit: Cells 112 by 30m; glands 1; diameter of glands 34m; 



length of multicellular protuberances 101m- 

 /. sloteri: Cells 82 by 34m; glands 2; diameter of glands 52m; length 



of multicellular protuberances 304m. 



In the hybrid, the number of glands is greater, the 



glands are larger, and the multicellular protuberances 



are larger, than in cither parent. (Plate 28, figs. 169, 



170, and 171.) 



Flower. 



The corolla is composed of three layers: the upper 

 epidermis, a spongy mesophyll, and a lower epidermis. 

 Portions of these layers were examined between two 

 points of the corolla limb. 



The upper epidermis is composed of papillose cells, 

 those of the hybrid being larger than in either parent. 

 (Plate 39, figs. 172, 173, and 171.) 



The sizes of cells of upper epidermis of the corolla 

 are for I. coccinea 25 by 17/x, I. quamoclit 22 by 17/i, I. 

 sloteri 29 by 22/x. 



The mesophyll of I. coccinea is not spongy, and is 

 composed of cells that are joined together without inter- 

 cellular spaces. That of I. quamoclit is very spongy with 

 large intercellular spaces and cells that are narrow and 

 many branched. That of the hybrid combines the charac- 

 ters of both parents. There is a very slight suggestion of 

 the cells narrowing into protuberances, but excepting 

 their greater size the cells rather resemble those of I. coc- 

 cinea. Large intercellular spaces are also present; these 

 are not as large as those of I. quamoclit. 



The lower epidermal cells of I. coccinea (Plate 29, 

 figs. 175, 176, and 177) are slightly wavy and thin-walled, 

 and the thickenings at the angles are very slight. Those 

 of 7. quamoclit are larger, with very wavy and slightly 

 thicker walls, and with more thickening at the angles 

 than in 7. coccinea. Those of the hybrid are larger than 

 in either parent, and the diameter of the walls is between 

 those of the parents as to wavincss and thickening at 

 the angles. 



The upper surface of the limb of the corolla in 7. coc- 

 cinea is of a Vermillion color with a small yellow area 

 around the opening of the corolla tube. The yellow 

 color is due entirely to the presence of deep yellow 

 chromoplasts in the upper epidermal cells. The Ver- 

 million is due to a combination of yellow chromoplasts, 

 which are present in all of the cells, with a, deep Vermil- 

 lion cell sap which is present in some of the cells. In 

 I. quamoclit the upper surface of the limb is crimson, 

 due to the presence of crimson cell sap and deeper crim- 

 son-red globules in the upper epidermal cells. Very 

 small plastids are seen in the cells, but which must be 

 either leucoplasts or very pale yellow chromoplasts, as 



the color, if present, is obscured by the deeply colored 

 cell-sap. In the hybrid the upper surface of the limb is 

 scarlet, a brilliant red with a trace of yellow due to a 

 combination of yellow chromoplasts, which are present 

 in all of the upper epidermal cells, with a pinkish red 

 cell sap which is present in some of them. 



The outer epidermal cells of the corolla tube are thin- 

 walled and only slightly wavy in I. coccinea; thick and 

 wavy in I. quamoclit; and intermediate in thickness and 

 waviness but larger in the hybrid. These cells contain 

 chromoplasts which are small and indistinct in I. cocci- 

 nea; but large and distinct in I. quamoclit and the hybrid. 



The sizes of the cells of the outer epidermis of the 

 corolla tube are for I. coccinea 68 by 11/*; I. quamoclit 

 58 by 11>; I. sloteri 98 by 14,*. 



The color of the exterior of the corolla tube in 7. coc- 

 cinea is yellow-orange to orange-red, due to the presence 

 of yellow chromoplasts in all of the outer epidermal cells 

 and to a pinkish-red cell sap in some cells. In 7. quamo- 

 clit the color is reddish-pink, due to the presence of a 

 pinkish-red cell sap in some cells and deeper red globules 

 in most of the cells. Colorless plastids are seen. In the 

 hybrid the color is vermillion-red, due to the presence of 

 yellow chromoplasts in all of the cells and a pinkish-red 

 cell sap in some, and to a few red globules in some cells. 



The color of the interior of the corolla tube in 7. coc- 

 cinea is deep yellow, due to the presence of deep orange- 

 yellow chromoplasts in the inner epidermal cells. In 

 7. quamoclit the color is pale pink. The inner epidermal 

 cells contain yellow chromoplasts. The pinkish appear- 

 ance is due to the reddish-pink color of the exterior of the 

 corolla tube showing through. In the hybrid the color is 

 orange-yellow, due to the presence of orange-yellow 

 chromoplasts in the inner epidermal cells. 



Stamens. 



Numerous multicellular glands, or glandular shaggy 

 hairs as they are termed by Solereder, are found at the 

 base of the filaments. They consist of a multicellular 

 pedestal and a large, ellipsoidal, glandular cell. (Plate 

 27, figs. 163, 164, and 165.) They are much longer in 7. 

 quamoclit than in 7. coccinea, and in the hybrid are prac- 

 tically mid-intermediate between the tivo parents. 



The lengths of the multicellular glands of the stamens 

 are for 7. coccinea 111.8*1, 7. quamoclit 408.5,*, 7. sloteri 

 275.2**. 



Comparative Summary of the Characters of the 

 Hybrid I. sloteri and its Parent-stocks. 



The hybrid was found to be : 



(1) The same or practically the same as the seed 

 parent in the following characters: In the length of pri- 

 mary root before branching, number of cork layers and 

 the average diameter of the pitted vessels, and the diame- 

 ter of the largest pitted vessels on the transverse section 

 of the root ; the number of cortex layers and the number 

 of secretory cells in the transverse section of the stem; 

 the number of stomata on the upper epidermis of the leaf 

 at the apex; the width of the lower epidermal cells of 

 the leaf at the base ; the depth of the epidermis on the 

 transverse section of the petiole. 



(2) The same or practically the same as the pollen 

 parent: In the number of capsules maturing on one 

 flower-stalk ; the number of sclerenchyma patches in the 



