. The fungi which cause plant disease . Plant diseases; Fungi. 102 THE FUNGI WHICH CAUSE PLANT DISEASE Asexual spores are either in sporangia or are borne as conidia. The sporangium is usually with a columella. The spore-bearing stalks exhibit the widest diversity in shape and form of branch- ing, Fig. 69. Sexual spores (zygotes) are produced through the union of two like gametangia. (Fig. 70.) Though the cytology of zygote formation has not been completely studied it seems clear that the fertilization is multi-nucleate ^^â ' as in Albugo bliti and that the two uniting elements are coenogamete
. The fungi which cause plant disease . Plant diseases; Fungi. 102 THE FUNGI WHICH CAUSE PLANT DISEASE Asexual spores are either in sporangia or are borne as conidia. The sporangium is usually with a columella. The spore-bearing stalks exhibit the widest diversity in shape and form of branch- ing, Fig. 69. Sexual spores (zygotes) are produced through the union of two like gametangia. (Fig. 70.) Though the cytology of zygote formation has not been completely studied it seems clear that the fertilization is multi-nucleate ^^â ' as in Albugo bliti and that the two uniting elements are coenogametes. Key to Orders of Zygomycetes Asexual spores borne in sporangia which in some genera are reduced to corddia-like bodies Asexual spores true conidia borne singly at the apex of the Mucorales, p. 102. Entomophthorales, p. 107 Mucorales (p. 66) This order is comprised mainly of saprophytes, about twenty genera and one hundred fifty species; but includes a few forms which prey upon vegetation in a very low ebb of life, as cells of ripe fruit, tubers, etc., and a few species which are of especial interest as they grow upon other fungi. The sporangial stage is exceedingly common; the zygosporic much less so, verj^ rare in the case of some species. Blakeslee ^-° has shown that in some species, though the two uniting sexual organs FiQ. 71.âPhycomycetes showing are to all appearances alike, the plants zygosporic lines at regions of . ^^ , i ^^n^ contact between + and â are in reality dicEcious; that a branch strains. After Blakeslee. r i ^ , , irom one plant cannot produce sexual organs that will unite with other sexual organs produced upon the same plant. Moreover, there appears to be a differentia- tion of sex in that one plant, which may provisionally be re-. 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 t
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfungi, bookyear1913
