. Fungi, ascomycetes, ustilaginales, uredinales. Fungi. Ill] ERYSIPHALES 83 walled over its upper surface, but an oval region remains thin on the lower side. As the ripening perithecium loses water so do the appendages; the thin area below the bulb is pushed in by atmospheric pressure, the under surface becomes consequently shorter than the upper and the end of the spine is pulled down till subsequent moistening straightens it again (Harper).. Fig. 40. Perithecia of a. Erysiphe tortilis (Wallr.) Fr.; b. Mia-osphaeria sp.\ c Aceris (DC.) Sacc; d. Phyllactinia Corylea (Pers.) Karst.; x 120. Unci
. Fungi, ascomycetes, ustilaginales, uredinales. Fungi. Ill] ERYSIPHALES 83 walled over its upper surface, but an oval region remains thin on the lower side. As the ripening perithecium loses water so do the appendages; the thin area below the bulb is pushed in by atmospheric pressure, the under surface becomes consequently shorter than the upper and the end of the spine is pulled down till subsequent moistening straightens it again (Harper).. Fig. 40. Perithecia of a. Erysiphe tortilis (Wallr.) Fr.; b. Mia-osphaeria sp.\ c Aceris (DC.) Sacc; d. Phyllactinia Corylea (Pers.) Karst.; x 120. Uncinula These hygroscopic movements may be repeated many times according to weather conditions, even after the living protoplast has disappeared from the appendage (Neger); and at last the perithecium is loosened from its attachment. In other cases, such as Erysiphe and Sphaerotheca, the appendages may help to anchor the perithecium to its host during development; in Uncinula necator their apices become mucilaginous (Salmon), and they serve, much as do the penicillate cells oiPhyllactinia, to attach the free perithecium upside down to the substratum. The development of the perithecium was first described in 1863 by 6—2. 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 Gwynne-Vaughan, Helen Charlotte Isabella (Fraser) Dame, 1879-. Cambridge [Eng] University Press
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfungi, bookyear1922
