. The elements of botany for beginners and for schools. Plants. larger part of the human race, consists of the long and woolly hairs which thickly cover the whole surface of the seed. There are also crests or other appendages of various sorts on certain seeds. A few seeds have an additional, but more or less incomplete covering, out- side of the real seed-coats called an 383. Aril, or Arillus. The loose and transparent bag which encloses the seed of the White Water-Lily (Fig. 418) is of this kind. So is the mace of the nutmeg; and also the scarlet pulp around the seeds of the Waxwork (Celastru
. The elements of botany for beginners and for schools. Plants. larger part of the human race, consists of the long and woolly hairs which thickly cover the whole surface of the seed. There are also crests or other appendages of various sorts on certain seeds. A few seeds have an additional, but more or less incomplete covering, out- side of the real seed-coats called an 383. Aril, or Arillus. The loose and transparent bag which encloses the seed of the White Water-Lily (Fig. 418) is of this kind. So is the mace of the nutmeg; and also the scarlet pulp around the seeds of the Waxwork (Celastrus) and Strawberry-bush (Euonymus). The aril is a growth from the ex- tremity of the seed-stalk, or from the placenta when there is no seed-stalk. 384. A short and thickish appendage at or close to the hilum in certain seeds is called a Caruncle or Strophiole (Fig. 419). 385. The various terms which define the position or direc- tion of the ovule (erect, ascending, etc.) apply equally to the seed: so also the terms anatropous, orthotropous, campylotro- pous, etc., as already defined (320, 321), and such terms as Hilum, or Scar left where the seed-stalk or funiculus falls away, or where the seed was attached directly to the placenta when there is no seed-stalk. Rhaphe, the line or ridge which runs from the hilum to the chalaza in anatropous and amphitropous seeds. Chalaza, the place where the seed-coats and the kernel or nucleus are organically connected, — at the hilum in orthotropous and campylotropous seeds, at the extremity of the rhaphe or tip of the seed in other kinds. Micropyle, answering to the Foramen or orifice of the ovule. Compare the accompanying figures and those of the ovules, Fig. 341-355. Fig. 415. A winged seed of the Trumpet-Creeper. Fio. 416. One of Catalpa, the kernel cut to show the embryo. Fig. 417. Seed of Milkweed, with a Coma or tuft of long silky hairs at one end. Fig. 418. Seed of White Water-Lily, enclosed in its aril. Fig. 419. Seed of Ricinus or
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectplants, bookyear1887
