SEED-COLORATION 401 



(7) The conditions under which seeds colour in leguminous pods 

 and in capsules are discussed in detail, and the black and brown forms 

 of coloration, including black mottling, are especially dealt with. 

 After observing that the coloration, early shrinking, and hardening of 

 the seed and its coats are so conspicuously associated with the early 

 drying of the fruit, that the presumption in favour of there being a 

 causal connection is very strong (more especially in the case of legumes), 

 it is shown that this view is untenable. The results of experiment 

 demonstrate that these changes in the seed can take place under 

 conditions so humid that the drying of the fruit is precluded. In a 

 word, the regime involved in the coloration, early shrinking, and 

 hardening of the seed and its coats, both in the legume and in the 

 capsule, is that which is displayed by the colouring, shrinking, and 

 hardening seed in the moist berry. The seed colours normally in 

 moist fruits and continues the process notwithstanding the drying of 

 the fruit. In some cases, however, as in black mottling, the complete 

 coloration of the seed is interfered with by the fruit's drying (p. 375). 



(8) The colours of unripe and mature seeds, that is, of pre-resting 

 and resting seeds, are then compared in legumes, capsules, and berries, 

 and the inference is drawn that unripe or pre-resting seeds are usually 

 white in capsules and green in legumes (p. 385). 



(9) It is pointed out that the colour of the coats of the resting 

 seed in leguminous plants has but little connection either with the 

 colour of the coats of the pre-resting or unripe seed, or with the colour 

 of the embryo in the pre-resting and resting states ; but it is indicated 

 that with unripe leguminous seeds green embryos and green coats 

 usually go together (p. 389). 



(10) The changes in colour which the green embryos undergo 

 when entering the resting stage and subsequently when germination 

 begins are then discussed in the cases of seeds of Poinciana^ Cassia^ and 

 Bauhinia. They all assume a pale yellow lifeless hue in the resting 

 seed, and, as illustrated by the seeds of Poinciana regia, display consider- 

 able lethargy in the waking up of the dormant embryo during the 

 germinating process. In some non-leguminous seeds, as with those of 

 Hura crepitansj the green embryo becomes decolorised and blanched 

 when entering the resting state (p. 391). 



(n) The colour of the hypocotyl in leguminous embryos, as with 

 green cotyledons, is shown to be sometimes white and sometimes green 



(P- 393)- 



(12) It is observed that whilst the embryos of leguminous resting 



seeds are usually pale yellow, green embryos are not uncommon in the 

 resting seeds of other orders (p. 394). 



(13) With regard to white embryos in leguminous resting seeds, it 

 is remarked that since in genera like Phaseolus and Canavalia^ where 



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