. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. EPIDERMIS. 89 secretion .appears in the walls between neighbouring cells: these may be called glands with intramural secretion, or shortly mtra?}iural glattds. Besides those which result directly from the presence of the secretion there are in most, but not in all cases, other peculiarities of form and structure connected with glandular cells. {a) Bladder-like dermal glands. The peculiarity of structure of the bladder-like glands consists in the appearance of the secreted body at the
. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. EPIDERMIS. 89 secretion .appears in the walls between neighbouring cells: these may be called glands with intramural secretion, or shortly mtra?}iural glattds. Besides those which result directly from the presence of the secretion there are in most, but not in all cases, other peculiarities of form and structure connected with glandular cells. {a) Bladder-like dermal glands. The peculiarity of structure of the bladder-like glands consists in the appearance of the secreted body at the limiting surface between cuticle and cell-membrane. While the form and turgescence of the cell remain the same, the secretion, as it increases in quantity, raises up the cuticle like a bladder: either the cuticle grows simultaneously, while its thickness remains the same or increases, or its surface growth does not keep pace with the increase of the secretion, and hence it becomes strongly stretched, and at last is easily burst. The stickiness of the surface arises from the fluid secretion thus set free by the bursting of the cuticle. The rent cuticle, according to Hanstein, may be repeatedly renewed on young parts. These phenomena are best seen in the glandular hairs. According to their external development these belong for the most part to the capitate form, and the. Figs. 31—34.—Glandular hairs of the petiole of Primula sinensis. Fig 31 (142). In a the secretion beginning, b, with a large secretory bladder; d an old hair, the bladder has burst and the upper part disappeared.—Figs. 32—34 (375) Fig. 32= a of Fig. 31. a' with intact secretory bladder lying in water; <t" after solution of the secretion in alcohol. Fig, 33. c end of hair, intact; (-' the same after solution of the secretion by alcohol. Fig. 34 = oT of Fig. 31 under higher power. position of the glandular structure and secretion is at the head. When the latter is the expanded head of a unicellular
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Keywords: ., bookcentury1800, bookdecad, booksubjectplantanatomy, bookyear1884
