Seed coat

“ By the parent it is provided with a protective wrapping, the seed coat, and beneath this the little embryo swells until it reaches a certain size, when as a ripe seed it severs its connection with the maternal organism. It is important to realise that the seed of a plant is not a sexual cell but a young individual which, except for the coat that it wears, belongs entirely to the next generation. It is with annual plants in some respects as with many butterflies. ”

“ As the fruit develops, the soft tissue of the septa extends between the single seeds; the ripe fruit is thus unilocular and many-seeded. The seed-coat is filled by the embryo, which has two large, folded, brittle cotyledons."
The last sentence conveys an erroneous impression. The two cotyledons, which form the seed, are not brittle when found in nature in the pod. They are juicy and fleshy. And it is only after the seed has received special treatment (fermentation and drying) to obtain the bean of commerce, that it becomes brittle.
Varieties of Theobroma Cacao. ”

“ The dry seeds must be whole, retaining their original seed-coat. In order to make them germinate they are placed in a clean sack and steeped in a vessel containing clean water, which should be occasionally stirred. Sack and trough should be large enough to allow for the swelling of the pulses to about three times their original size. In a hot climate six to twelve hours is sufficient for this soaking. ”

“ Fruit a nearly spherical 1-seeded berry containing the rudiment of the second cell and tipped with the short remnant of the style, surrounded at base by the persistent reflexed sepals; flesh becoming thick, dark purple, and juicy at maturity. Seed short-oblong to subglobose, solitary, suspended; seed-coat thin, coriaceous, orange-brown and lustrous; embryo subglobose, filling the cavity of the seed; cotyledons fleshy, plano-convex, puberulous; radicle superior, very short, uncinate, turned toward the small hilum and inclosed in a lateral cavity of the seed-coat. ”

“ The normal characters: colour of cotyledons and seed-coats.
Culinary peas (P. sativum, omitting purple sorts) can primarily be classified on colour into two groups, yellow and green. In the green certain pigmentary matters persist in the ripe seed which disappear or are decomposed in the yellow as the seed ripens. But it may be observed121 that the “green” class itself is treated as of two divisions, green and blue. In the seedsmen’s lists the classification is made on the external appearance of the seed, without regard to whether the colour is due to the seed-coat, the cotyledons, or both. ”

“ In other cases the hard seed-coat itself is bright-coloured as in the scarlet seeds of Abrus precatorius, the so-called weather-plant. Animals also act as the agents of distribution in the case of fleshy edible pods containing seeds with a hard smooth testa, which will pass uninjured through the body, as in tamarind and the fruit of the carob-tree (Ceratonia) . ”

“ Every moment more of these seed coats ruptured, and even as they did so the swelling pioneers overflowed their rent-distended seed-cases, and passed into the second stage of growth. With a steady assurance, a swift deliberation, these amazing seeds thrust a rootlet downward to the earth and a queer little bundle-like bud into the air. In a little while the whole slope was dotted with minute plantlets standing at attention in the blaze of the sun. ”

“ The soft cotton is the warm coat for the cotton plant seed-baby. The fleecy wool is the warm coat of the sheep, or the little lambs. The web from the silk worm’s cocoon is the cradle in which it sleeps. Linen is made from the stalks of the flax plant.
When these materials are spun, or twisted, into long threads, we have spool cotton and silk, wool yarns, and linen thread, for sewing. ”

“ The seed coats have a certain influence in determining germination at the proper time, inasmuch as they make it difficult for the seed to germinate under the stimulus of a quantity of warmth and moisture insufficient to support the seedling. ”

“ In hulling seed the rasps or concaves of the machines scratch the seed coats sufficiently to permit water to penetrate them, so that the germination is greatly increased. Apparently there is no reason why southern-grown seed when it is properly hulled should not germinate as well as northern-grown seed. ”

“ Cotton thus planted in thin soil, will mature and open as soon as that which has been planted three weeks sooner in bottom lands.
When the earth is moist and warm, cotton-seed will sprout, and be up in about five or six days; but if the soil be dry it takes much longer—or until there is rain sufficient to saturate the loose earth: for the seed, being covered with a thick coat of coarse wool, is not so readily, as some other seeds, acted upon by slight moisture. ”

“ The Original of the outer Coat, though from Parts of the same substantial nature, yet is differently made. In a Plum, the Seed-Branch which runs, as is described, through [174] the Stone, is not naked, but, as is said, invested with a thin Parenchyma, which it carries from the Stalk along with it; and which, by the Ramification of the said Branch within the Stone, is in part dilated into a Coat. That of a Bean is from the Parenchyma of the Cod; the superficial part of which Parenchyma, upon the large peduncle of the Bean becoming a thin Cuticle, and upon the Bean it self a cartilaginous Coat. ”

“ Germination of Bean.—The common bean, as we have seen (Fig. 15) , has cotyledons that occupy all the space inside the seed-coats. When the hypocotyl, or elongated caulicle, emerges, the plumule leaves have begun to enlarge, and to unfold (Fig. 18) . The hypocotyl elongates rapidly. One end of it is held by the roots. The other is held by the seed-coats in the soil. It therefore takes the form of a loop, and the central part of the loop “comes up” first (a, Fig. 19) . Presently the cotyledons come out of the seed-coats, [24] and the plant straightens and the cotyledons expand. ”

“ The external coat of seeds is often of great interest, and needs to be dissected off before it can be rightly examined. The simplest plan in such a case is to boil the seed well, press it while still warm into a plate of wax, and then dissect with a pair of needles, forceps, and scissors under water. Many seeds may also be mounted in cells as dry objects, after being thoroughly dried themselves. ”

“ Seed of Milkweed, with a Coma or tuft of long silky hairs at one end.
382. The shape and the markings, so various in different seeds, depend mostly on the outer coat. Sometimes this fits the kernel closely; sometimes it is expanded into a wing, as in the Trumpet-Creeper (Fig. 415) , and occasionally this wing is cut up into shreds or tufts, as in the Catalpa (Fig. 416) ; or instead of a wing it may bear a Coma, or tuft of long and soft hairs, as in the Milkweed or Silkweed (Fig. 417) . The use of wings, or downy tufts is to render the seeds buoyant [Pg 126] for dispersion by the winds. ”

“ Within are a few seeds, hard and smooth. Why are they so hard? Will it not be difficult for such seeds to get moist enough and soft enough to enable them to germinate? The hard coats enable the seeds to remain uninjured for a long time in the water, in case one or two cells of the papery pods are broken open; and after the tough pod has decayed and the seeds have sunken to the moist earth among the sticks and dead leaves, they can have all the time they need for the slow decay of their armor. Sooner or later a tiny plant is likely to appear and produce a beautiful bush. ”

“ A large part of our clothing is made from the cotton that grows on the seeds of the cotton plant. The plant did not make the cotton for us, but probably to enable its seeds to be carried away by the wind and firmly fastened to the ground, when they lodged there. For a cotton seed clings very tightly to the earth, particularly after it has been wet. ”

“ No data have been secured on winter seeding in those portions of the United States where open winters do not occur. It is probable that in those sections the winters are sufficiently cold to prevent germination before spring. Good results may be obtained by winter seeding, but as usually no trouble is experienced in those sections in obtaining a stand by seeding as soon as the soil can be worked in the spring, it is strongly recommended that seeding be done with hulled seed, which germinates well at this time of the year. ”

“ Fleshy seeds, such as chestnuts, are usually planted as soon as they ripen and fall. When seeds are covered with a fruity coat, like holly berries, for example, the berry should be soaked in water for a few days until the seeds can be squeezed free of the pulp. Hard-coated seeds need to be gently cracked, or nicked, to hasten germination, and can be sown outdoors in the fall to germinate the following spring, or even the spring after that. ”

“ A seed of “Sea Island cotton” is covered with long hairs only, which are readily pulled off, leaving the comparatively small black seed quite clean or with only a slight fuzz at the end, whereas a seed of “Upland” or ordinary American cotton bears both long and short hairs; the former are fairly easily detached (less easily, however, than in Sea Island cotton) , whilst the latter adhere very firmly, so that when the long hairs are pulled off the seed remains completely covered with a short fuzz. ”

“ The factor of seed selection in cotton growing is of the greatest importance and yet I think it is safe to say that over 75 percent, of the growers of upland cotton, and indeed many Sea Island cotton growers, pay no attention to it, simply taking their seed from the pile at a public gin, for instance, without any reference to the variety, vigor, productiveness, etc. It is entirely a matter of chance as to whether they get poor and worthless seed or seed of fair quality. Superior seed of any strain could never be obtained in this way other than as a rare accident. ”

“ The bed should be disked or harrowed just before planting the cotton seed, but it is seldom advisable to re-bed the land just before planting. Cotton comes up quicker, grows off faster and begins bearing sooner on a well settled, firm seed bed. It is not wise to plant the cotton on freshly prepared land. ”

“ In clear weather after the dew has disappeared the approximately ripe plants or seed heads must be harvested and spread thinly—never packed firmly—upon stout cloth such as ticking, sailcloth, or factory cotton. A warm, open shed where the air circulates freely is an admirable place, since the natural temperature of the air is sufficient in the case of seeds to bring about good results. Usually in less than a week the tops will have become dry enough to be beaten out with a light flail or a rod. In this operation great care must be taken to avoid bruising or otherwise injuring the seed. ”

“ The points of half-ripened shoots make the best cuttings, and therefore the summer season will be found the most suitable for increasing the stock of the small growing kinds. The spring is the proper time for sowing the seed, which should be soaked in warm water some time previously. Whether raised from cuttings or seeds, the young plants will require stopping once or twice after they are established in the small pots in which they are put when potted off singly, to induce them to produce an abundance of side shoots, and thus form a good foundation for bushy specimens. ”

“ In the seedbed made out of doors in early spring, the drills may be made 4 to 6 inches apart and the seeds sown at the rate of 5 or 6 to the inch. A pound should produce enough plants for an acre. In hand sowing direct in the field, a fine [Pg 139] dry sand is often thoroughly mixed with the seed to prevent too close planting. The proportion chosen is sometimes as great as four times as much sand as seed. Whether sown direct in the field or transplanted the plants should finally not stand closer than 8 inches—10 is preferred. ”

“ This bud presently opens into a pair of well-formed maple leaves.
As these leaves increase the seed-leaves diminish; the plant is feeding upon them. The ascending stem presses its first pair of leaves upward, forms between them two more, and then two more, and thus on.
Small branches are formed by the end of summer, the seed-leaves are exhausted, and the plant is doing its own work.
Under the trees in March we find many interesting examples of seed-growth. The feeding or seed-leaves of the young plant are called cotyledons. All flowering plants have cotyledons ”

“ Cutting should be done when the greater proportion of the seeds are hard, but not sufficiently ripe to shell. At this stage a majority of the pods are turned a dark-brown color and the seeds are fully developed. Frequently the cutting can be raked into windrows after two hours if the weather is drying, and in two or three hours more put into cocks and let stand for twenty-four to forty-eight hours, as the weather may justify. It should, however, be well cured and thoroughly dry when put in the stack, or there is danger of heating, and stack-heating seriously injures the vitality of the seed. ”

“ Summer-flowering, or Ten-week Stocks.—These annual varieties include a wonderful range of colours, as well as considerable diversity in the habit of growth. For their brightness, durability, and fragrance they are deservedly popular. It is usual to sow the seed under glass from the middle to the end of March. Pans or shallow boxes, filled with sweet sandy soil, make the best of seed-beds, and it may be well to say at once that no plants pay better for care and attention than the subjects now under consideration. ”