. Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae. Plant diseases; Parasitic plants; Fungi. SCLEROTINIA. 257 leaves of Vaccinium Vitis-Idaca exhibit in spring a mould- like coating, consisting of chains of lemon-shaped conidia. Woronin thus describes it: " In the outer layers of the cortex, amongst the dying elements, a pseudoparenchymatous cushion is formed, from which simple or dichotomously branched hyphae grow out through the overlying cuticle. The individual members of the chains of conidia are sep
. Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae. Plant diseases; Parasitic plants; Fungi. SCLEROTINIA. 257 leaves of Vaccinium Vitis-Idaca exhibit in spring a mould- like coating, consisting of chains of lemon-shaped conidia. Woronin thus describes it: " In the outer layers of the cortex, amongst the dying elements, a pseudoparenchymatous cushion is formed, from which simple or dichotomously branched hyphae grow out through the overlying cuticle. The individual members of the chains of conidia are separated from one another by a spindle-shaped piece of cellulose—'the disjunctor.'" The disjunctor spoken of here is a spindle-shaped cellulose body found between the single conidia; it easily breaks across and so facilitates the breaking up of the chains of conidia. Fio. 135.—Sclerotinia vacciniion Vacciaium VUis-hlaea. Mummified Cowberries in fresh condition and in the following May, after development of Peziza-cw^s. A, Chain of conidia united by disjunctors. B, Germinating conidium after treat- ment with iodine ; the plasma has shrunk, but remains connected with the sporidia in process of abjunction. (After Woronin.) (Fig. 135). It has its origin as follows: The conidia at first lie closely end to end, enclosed in a delicate primary membrane ; the partition-membranes split into two lamellae, each of which takes part in the formation of a cellulose body which gradually becomes spindle-shaped. In the course of its growth this cellulose body—the disjunctor—ruptures the primary enclosing membrane, and, being released, becomes more elongated, so that the conidia are pushed away from each other and fall apart. The conidia have a strong characteristic odour of almonds, attractive to insects, which carry off the conidia and dust them on the stigmata of other Vaccinium flowers. Wind is also, in all probability, an agent in the distribution of the conidia. The R. Please not
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherl, booksubjectfungi
