. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. CHAP. IT.^DIFFERENTIATION OF THE THALLUS.—SIMPLE SPOROPHORES. 47. Fig. 20. Pkytofhtkora in/estans, extremity of two simple sporophores. a forma- tion of the first gonidia on the tip of each branch, b two ripe gonidia on each branch, with the beginning of the formation of a third. Magn. about 200 times. put out branches bearing new sporangia. There is here therefore a cymose branching of the sporangiophores. The gonidiophores in Feronospora, which are also without tran
. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. CHAP. IT.^DIFFERENTIATION OF THE THALLUS.—SIMPLE SPOROPHORES. 47. Fig. 20. Pkytofhtkora in/estans, extremity of two simple sporophores. a forma- tion of the first gonidia on the tip of each branch, b two ripe gonidia on each branch, with the beginning of the formation of a third. Magn. about 200 times. put out branches bearing new sporangia. There is here therefore a cymose branching of the sporangiophores. The gonidiophores in Feronospora, which are also without transverse septation, are repeatedly forked or monopodially paniculate. The branches are all at first narrowly conical, and when their longitudinal growth is completed their terminal portions swell into an ovoid form, as is seen in Fig. 20 a, and are abjointed to form gonidia, and with this the de- velopment of a gonidiophore of Peronospora comes to an end. But in the nearly aUied genus Phytophthora after the abjunction of each goni- dium the narrow end of the branch which bore it swells slightly immediately beneath it, and elongating at the same time pushes the gonidium so much to one side that it pre- sently forms a right angle with the pedicel. Then in P. infestans the gonidiophore swells at the point of attach- ment of the gonidium into a small narrowly flask-shaped vesicle, and its upper end elongates at the same time and again assumes the character of a gonidia-forming point. After a time a gonidium is formed on it in the manner described above, and the process is repeated usually three or four times on the same gonidiophore, or as many as twelve or fourteen times in luxuriant plants. Older simple gonodiophores therefore, when examined dry, are seen to bear a number of lateral nearly equidistant gonidia forming a ri_ght-angle with the gonidiophore, and each standing on a flask-shaped swelling (Fig. 20 b). As the ripe gonidia fall off" instantly in water, preparations t
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