3434 



VANILLA 



VARIEGATION 



vanillin crystallizes on the outside. For a full descrip- 

 tion of vanilla culture and methods of curing the pods, 

 see Bulletin No. 21, United States Department of 

 Agriculture, Division of Botany, by S. J. Galbraith. 

 Vanillin is also made from other sources by chemical 

 means. 



planifolia, Andr. (V. aromdtica, Willd., in part). 

 COMMON VANILLA. VANILLA BEAN (from the pods). 

 Fig. 3905. Tall climbing herbs with stout sts.: Ivs. 

 thick, oblong-lanceolate, acuminate, with short, stout 

 petioles: fls. yellow, large, in axillary racemes of 20 or 

 more blossoms; sepals and petals oblanceolate; label- 

 lum trumpet-shaped, with small, reflexed, crenulate 

 lobes. Winter. A native of Mex., but widely cult, 

 throughout the tropics and in greenhouses. B.M. 7167. 

 L.B.C. 8:733. G.C. III. 25:213. Gn. 57, p. 35. O. 

 4:8. Partially epiphytic. 



aromatica, Sw. St. angular: Ivs. broadly ovate, with 

 a bluntish point, contracted at the base : fls. greenish and 

 white. Jamaica, Colombia, Trinidad. 



V. figgersii, Rolfe. Sts. thick: Ivs. abortive, oblong-lanceolate: 

 sepals and petals greenish; lip white or lilac. W. Indies. V. 

 grandifdlia, Lindl. Lvs. 7 in. long, 5 in. broad, narrowed at base 

 into more or less elongated petiole: fls. very large. W. Trop. Afr. 

 V. Humblotii, Reichb. f. Fls. bright yellow, about 5 in. across, with 

 brown markings on lip and rosy hairs in throat. Madagascar. B.M. 

 7996. V. Liijse, Wafden. Lvs. resembling V. planifolia: fls. very 

 large. Congo. HEINRICH HASSELBRING. 



GEORGE V. NASH.| 



VARIATION: See Breeding, page 547. 



VARIEGATION. This term is usually applied to a 

 class of variations, especially in leaf -coloration, in which 

 the leaves become striped, banded, spotted, and 

 blotched with yellow, white, red, and various other 

 colors in connection with the normal green of other por- 

 tions of the leaves. In the case of yellow-and-white 

 variegation, the term albinism is sometimes used, espe- 

 cially when the plants are largely marked with white or 

 yellow, as in AbwtUon Sellovianum, Pelargonium zonale, 

 and variegated forms of Evonymus japonica, Hydrangea 

 hortensis, Hedera helix, Polyscias Guttfoylei var. Vic- 

 torise, and others. 



Among the dracenas, caladiums, and codieums, be- 

 sides the white variegation, there are developed beauti- 

 ful reds, pinks, yel- 

 lows, and so on. As 

 a rule, the term 

 variegation is not 

 used in cases of 

 color - variation in 

 which only the sur- 

 face of the leaf is in- 

 volved, as in many 

 of the begonias, 

 o^ysansevierias (S. 

 *j thyrsiflora and *S. 

 zeylanica}, Alocasia 

 cuprea, Cissvx dis- 

 color, and others. 

 In many such plants 

 the markings are 

 due in part to hairs, 

 scales, or air in the 

 cuticle or epidermal 

 cells, as in sanse- 

 vieria and begonia. 

 In some begonias, 

 many varieties of 

 calathea (as C. or- 

 nata var. aibo-lin- 

 eata), the epider- 

 mal cells develop 

 decided and definite 

 color-variation, 

 though the changes 

 3906. Variegation in abutilon. do not usually 



involve the mesophyl or inner cells of the leaf. In some 

 genera, however, especially calathea, all gradations are 

 found between purely epidermal variegation and changes 

 involving the deeper layers of the leaf, as in C. Veitchii 

 and C. Makoyana. The same is true of many other 

 genera. Different kinds of variegation are shown in 

 Figs. 3906, 3907. 



True variegations may be distinguished from ordinary 

 colorations, bleaching, chlorosis, and the like, by the 

 fact that the colored areas are usually quite sharply 

 denned. They do not gradually blend into each other, 

 but have definite boundaries. Cells in the variegated 

 areas are found, as a rule, to contain the same chlorophyl 

 bodies (chromatophores) as the ordinary green cells of 

 the plant. However, in the variegated parts, the green 

 color is not developed, and the chromatophores are 

 often smaller or are somewhat swollen and vacuolate. 

 In the case of chlorosis due to the lack of iron, or yel- 

 lowing due to the lack of light, a leaf will quickly develop 

 its normal color if given the proper conditions. This is 

 not the case, however, in variegated leaves. While the 

 intensity of whatever color the chromatophores may 

 have can be varied by light and food, a variegated cell 

 can never be changed by these means to a normal cell. 



The chlorophyl granules (chromatophores) appear to 

 have lost entirely, in many cases, the power to make 

 starch and sugar from the carbonic acid gas in the air, 

 and in other cases this power is very greatly reduced. 

 In practically all cases, however, when the chromato- 

 phores are not destroyed, they retain the power to con- 

 vert sugar into starch and they thus store up starch in 

 then* tissues from the sugar manufactured by the 

 healthy cells of the leaf. 



WTiite or albino variegation is of course due to a lack 

 of any coloring in the chromatophores, and sometimes 

 to the entire absence of these bodies. The cells seem to 

 have lost completely the power of making chlorophyl. 

 These albicant variegations are to be looked upon as 

 the more extreme forms of variegation, and usually arise 

 through a feeble or atrophied condition of the plant. 

 Seedlings raised from parents both of which are varie- 

 gated in this way are usually very weak. High feeding 

 and favorable conditions of growth, while they will not 

 cause a variegated plant to return to its normal con- 

 dition, will often stimulate the development of a normal 

 green shoot that takes most of the nourishment and 

 thus causes the starvation and disappearance of the 

 albicant parts. In other cases, as in codieums, modified 

 chlorophyl is made. Large yellowish oil-like drops occur 

 in the substance of the chromatophores, and the various 

 changes that these undergo, as the leaf becomes older, 

 produce the remarkable and beautiful colorations of 

 this group of plants. The coloration here, as in dracenas 

 and caladiums, is intensified by strong light and 

 nourishing food. The more of the modified chlorophyl 

 there is produced and the more rapid the changes hi the 

 modified chlorophyl brought about through the action 

 of light and the acids and oxidising ferments of the 

 leaves, the more highly developed will be the colors, 

 though here again high feeding is likely to cause the 

 plant to revert to its normal condition. 



Variegated plants or parts of plants are usually of 

 slower growth and smaller than green plants of the 

 same variety or the green parts of the same plant. 



Variegation occurs either by bud-variation or by 

 variations in seedlings. In the former, a variegated 

 branch is likely to appear on an otherwise perfectly 

 normal plant. Such variegations are easily repro- 

 duced by budding, grafting, or cuttings, but generally 

 do not develop again from seeds produced on such 

 branches. On the other hand, when variegation 

 develops in seedlings, the seeds of such plants usually 

 give a number of variegated individuals, even the coty- 

 ledons being sometimes affected. In some cases the 

 proportion of variegated plants from seeds is very large 

 and can be increased by selection. As a rule, the form of 



