. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. HAIKS. 179 ened with water (or better still in a freth state), they are dis- tinctly blue. 4. The protein layer, the cells of which contain granular albuminoid matters. The layers just described are different in different seeds, and sometimes different in different parts of the same seed-coat, so that the division has really little utility. 505. The external in- tegument or testa may have well-developed hairs, as has been shown in Vol- ume I. p. 306. Only one o
. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. HAIKS. 179 ened with water (or better still in a freth state), they are dis- tinctly blue. 4. The protein layer, the cells of which contain granular albuminoid matters. The layers just described are different in different seeds, and sometimes different in different parts of the same seed-coat, so that the division has really little utility. 505. The external in- tegument or testa may have well-developed hairs, as has been shown in Vol- ume I. p. 306. Only one of these cases of hairs can be here described; namely, those which form the felted covering of cot- ton-seeds, and which are the "cotton" of commerce. These are slender cells with col- lapsed walls. As they ap- proach maturity, the cells become more or less twisted ; the resulting spiral is that which imparts to cotton its value as a material for spin- ning. Some other seeds, notably those of species of Asclepias, have long and strong hairs, but none of these have any spiral twist which fits them for textile purposes. Regarding the size of cot- ton "fibres" (hairs of the seed), the following meas- urements by Ordway are of interest: Maximum length in the "sea-island" variety, about two inches (five centimeters); in Pig. 136. Cross-sections of cotton-fibres. A A, unraature fibres; B B, half-mature fibres; CO, fuliy mature fibres; Z>, section of fibre, sliowing laminated cell-walls. (Bowman.) Fig 137. ..4, Glassy, structureless fibre; 5, thin, pellucid, iuiraature fibre; C, half mature fibre, with thin cell-wall; I> and E, fully mature fibre, with full twist and well- defined cell-wall. (Bowman.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Goodale, George L. (George Lin
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