Vitality may be shown by curve for germination-capacity for a few years only ; most 

 seeds die within a year or two if kept dry. Seeds buried in damp soil without oxygen 

 probably deteriorate more rapidly : a dead seed does not germinate, and conversely. 



(1) Phaaoolus (Kidney Bean); Smooth coloured testa with conspicuous lateral 

 hilum ; soaked seeds increase to twice their volume dry, showing micropylc at one end 

 of hilar scar (7 mm.), and chalazal knob at the other. No trace of endosperm ; 

 leathery testa enclosing embryo with 2 massive cotyledons, small radicle, 4 mm., 

 pointing to micropyle, and plumule (5 mm.) with young leaves folded, between cots. 

 Section of cots, shows uniform parenchyma (100-150 /x diam.), with rather thick walls 

 (6 /A), and abundant starch-content; grains oval, 30-50^ with central hilum; also 

 granular proteid. Testa non-lignificd, with conspicuous prismatic layer on surface ; 

 cells much thickened, small basal lumen (70 /x by 10). 



Vicia Faba (Broad Bean) essentially similar, with black hilum, flatter cotyledons, 

 radicle conspicuously outlined. 



(2) Helianthus (Sunflower): Fruits sold for ' seed '-purposes are dry achenes, 

 indehiscent, enclosing one seed : crack off fruit-wall from soaked ' seeds ' to see 

 membranous testa, relic only, no endosperm, straight embryo, with adpressed cotyledons 

 (9 mm.), straight radicle (9 mm.), and minute pointed plumule. Section of cots. 

 shows no starch, but abundant fat (running to oil-drops on adding KOH) in thin- 

 walled cells (40 /x or so) grading to 3-ranked palisade on upper surface (100 /x deep). 



(3) Aucuba : Scarlet berries particularly good in spring months ; each containing 

 one large seed, not dried off: testa thin and undifierentiated ; endosperm an ovoid 

 mass of thick-walled pitted cells, with aqueous contents and little fat. Embryo small, 

 but accurately centred at apex below stigma of fruit, and cut in median plane: 

 rounded radicle, and plumule, with good apical differentiation, as cleared in KOH. 

 Adapted for germination at the forest-base. 



(4) HicinuB (Castor-Oil Plant) : Dry seeds with glossy marbled coat, with 

 1 caruncle ' growth over micropyle. In soaked seeds note testa of i densely sclerosed 

 prismatic layer (peripheral layers dried off), only cut in developmental stages of green 

 fruit, and residual inner parenchyma as white skin, enclosing cake-like mass of 

 endosperm of thin-walled parenchyma (about 50 jx) storing fat and aleurone grains. 

 Embryo with two thin, veined, cots, laid out in median plane, following shape of 

 endosperm ; small radicle and plumule. Sections of endosperm, cleared in ether, 

 mounted in water, show aleurone grains (10-12 /x), many in each cell, differentiated 

 into crystalloid of globulin, and a globoid (3 /*). Salt-solution on spirit-material 

 dissolves the crystalloid ; the rest of the grains cleared in KOH, and the globoid of 

 CaMg Phosphate in acetic acid. A xerophytic tropical seed. 



(5) Aesculus (Horse-chestnut): largest available tree-seed in autumn; ij in. 

 diam., testa thick (ij mm.), no endosperm, embryo massive. Broad hilum (20 mm.) 

 with pattern of radicle at one side gives orientation for cutting in median plane : note 

 radicle in pointed pocket-like end of curved ovule, plumule, and cotyledons, often 

 with central space imperfectly filled; cots, store starch as oval grains (15 /x) in 80 ft. 

 parenchyma. Testa non-lignified, stained with tannin, of small units, little differen- 

 tiated. Seed not dried off. 



(6) Juglans (Walnut) : Most elaborate seed of available tree-types (autumn). In 

 soaked 'seeds', note ' shell '=sclerocarp of a Drupe-fruit, cracking in 2 valves (not 

 carpellary portions). Seed, removed from 4 pocket-chambers of fruit, separated by 

 plate-partitions, shows 4 main lobes; each cot. bilobed, and lobes crumpled or 

 convoluted irregularly. Cotyledons orientated in same sense as the shell-valves: to 

 see both, and plumule, cut across in plane at right angles to dehiscence-line. Main 

 root-apex at pointed end ; plumule with leaf-rudiments. Section of cot. lobes shows 

 food stored as fat in thin-walled parenchyma ; testa of vestigial layers, V.B., and 

 aqueous epidermis (60 /x); endosperm relic, of 1-2 outer layers, storing fat, following 

 the testa and peeling off with it ; seed not dried off. In development the endosperm is 

 formed as a scanty lining, and the cavity of the seed is filled with fluid (July). The 

 gelatinous endosperm is replaced by embryo (August), and the cot. lobes extend 

 to fill the pocket-cavities modelled in the massive ovary-wall. 



(7) Hedera (Ivy): seeds small, 3-5 in 'berry '-like fruit, each covered by 

 parchment-like sclerosed sclerocarp. Testa thin and membranous ; embryo small ; 

 endosperm stores fat, and is ruminated; rain-washed pyrenae suggest grains of corn. 



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