. The botany of crop plants; a text and reference book. Botany, Economic. 264 BOTANY OF CROP PLANTS brac\eo\e bility that the soil is more quickly exhausted by seeded hops than by seedless ones. The Mature Fruit.—The fruit (Fig. 105) is a small achene surrounded by the persistent cup-shaped perianth. The single seed within has a curved embryo about which is a small amount of endosperm. Lupulin Glands.—In the ma- ture hop, the outer surface of the bracteoles, the perianth, and, to a less extent, the bases of the bract-Hke stipules are covered with yellow pollen-like grains, the so-called "
. The botany of crop plants; a text and reference book. Botany, Economic. 264 BOTANY OF CROP PLANTS brac\eo\e bility that the soil is more quickly exhausted by seeded hops than by seedless ones. The Mature Fruit.—The fruit (Fig. 105) is a small achene surrounded by the persistent cup-shaped perianth. The single seed within has a curved embryo about which is a small amount of endosperm. Lupulin Glands.—In the ma- ture hop, the outer surface of the bracteoles, the perianth, and, to a less extent, the bases of the bract-Hke stipules are covered with yellow pollen-like grains, the so-called " hop-meal" or "lupuHn" (Fig. 105). Each yellow grain is a cup- shaped, multicellular, glandular hair filled with a resinous secre- tion. It is an outgrowth of an epidermal cell and consists of a short stalk and a cup of one layer of cells. Each cell has a rather thick cuticle. The secre- tion of the cells collects just beneath the cuticle, raising the latter up until finally the cup-shaped depression is filled with the secretion which remains covered by the cuticle itself. In immature hops, the lupulin glands are bright yellow and transparent. In mature hops, they are a paler yellow and somewhat opaque. The commercial value of hops depends entirely upon the amount and quality of the "; It constitutes from 15 to 32 per cent, by weight of the hop. Geographical.—The hop grows wild in England, the. Fig. 105.—Hop (Humulus lupu- lus). A, bracteole; B, immature lupulin gland; C, same in section; D, mature lupulin gland; E, same in section. (B-E after Percival.). 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 Robbins, Wilfred William, 1884-1952. Philadelphia, P. Blakiston
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectbotanyeconomic
