. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 150 DIGESTIVE GLANDS The tentacles of the Sundew (Drosera) are much more elabo- rate, being supplied with a vascular bundle which extends into the slightly enlarged tip. In the latter the bundle is enveloped by three distinct layers of cells, of which the innermost is thick- ened after the manner of an endodermis, while the two outer layers which contain the crimson pigment are those actually concerned in secretion ; the superficial one has a palisade-like structure. The tentacles of the Sundew, like many oth
. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 150 DIGESTIVE GLANDS The tentacles of the Sundew (Drosera) are much more elabo- rate, being supplied with a vascular bundle which extends into the slightly enlarged tip. In the latter the bundle is enveloped by three distinct layers of cells, of which the innermost is thick- ened after the manner of an endodermis, while the two outer layers which contain the crimson pigment are those actually concerned in secretion ; the superficial one has a palisade-like structure. The tentacles of the Sundew, like many other digestive glands, serve not only for the secretion of the digestive fluid, but also to ^lYV. absorb the pro- ducts of its action; in addi- tion they pro- duce the ad- hesive mucilage which forms a thick glistening laj'er over the head of the tentacle. The Bladder- wort {Utricii- laria) is stated to secrete no di-. FiG. 75.—Transverse section through a small part of the leaf of the Butterwort (Piiiguicula), showing the short digestive glands (d.) and a mucilage- secreting hair (»(.). gestive fluid, the four-armed hairs which occur on the inner surface of the bladders serving solely for the absorption of the products of decay of the minute bodies of the entrapped animals. Various digestive ferments are likewise secreted hy the sur- face of the cotyledons of albuminous seeds whereb\' the food- substances in the endosperm are changed into a diffusible form. In general there is no differentiation of a special secreting laj-er, although in Grasses the palisade-like epidermal cells of the scutellum, in contact with the endosperm, are glandular in char- acter. These same cells are also concerned in the absorption of the digested Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Fritsch, Felix E
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpl, booksubjectplants
