A practical course in botany : with especial reference to its bearings on agriculture, economics, and sanitation . m. Can you make out what the narrowwhite line running through the center of the endosperm, divid-ing it into two halves, represents? Make a similar sketch of a cross the samewhite line runninghorizontally acrossthe endosperm, di-viding it into twoequal parts. Tofind out what theselines are, take an-other seed (alwaysuse soaked seeds fordissection) and remove the coats without injuring the the kernel carefully round the edges, remove half theendosperm, a
A practical course in botany : with especial reference to its bearings on agriculture, economics, and sanitation . m. Can you make out what the narrowwhite line running through the center of the endosperm, divid-ing it into two halves, represents? Make a similar sketch of a cross the samewhite line runninghorizontally acrossthe endosperm, di-viding it into twoequal parts. Tofind out what theselines are, take an-other seed (alwaysuse soaked seeds fordissection) and remove the coats without injuring the the kernel carefully round the edges, remove half theendosperm, and sketch the other half with the delicate em-bryo lying on its inner face. You will have no difficultynow in recognizing the linos in your drawings as sections ofthe thin cotyledons. Where is the hypocotyl, and which waydoes its base point ? Remove the embryo from the endosperm,separate the cotyledons with a pin, hold them up to the light,and observe their beautiful texture. Sketch them under thelens, showing the delicate venation. Is there any plumule ?Test the endosperm with a little iodine. Does it give a. Figs. 20-22.—Castor bean (slightly magnified) ; 20,back \iew ; 21, front view ; ch, chalaza ; r, rhaphe ; ca,caruncle ; 22, vertical section ;en, endosperm ; cc, cotyle-dons ; hy, hypocotyl; hi, hilum ; m, micropyle. THE SEED 17 blue or a brown reaction ? Crush another bit of it on a pieceof white paper and see if it leaves a grease spot. What doesthis show that it contains ? Test the embryo in the same way,and see whether it contains any oil. Note. — It should be borne in mind that the castor bean bears no rela-tion whatever to the true beans. It belongs to the sp-ge family, whi(^his botanically very remote from that of the peas and beans.
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