ERVILINA. 



[ 244 ] 



ERYSIPHE. 



1-650 to 1-420". The pedicle becomes ag- 

 glutinated to foreign bodies. 



BIBL. Duj. Infus. p. 455. 



ERVILINA, Duj. A family of Infusoria. 



Char. Body oval, more or less depressed, 

 partly covered by a membranous persistent 

 carapace, furnished with cilia upon the ex- 

 posed parts, and having a short pedicle re- 

 sembling a tail. 



Reproduction by transverse division. 



Two genera : Ervilia, carapace open in 

 front and on one side ; and Trochilia, cara- 

 pace open in front only. 



Dujardin questions whether Urocentrum, 

 E. does not belong to this family. 



BIBL. Duj. Infus. p. 454. 



ERUPTIONS/cuTANEOus. The scales, 

 crusts, scabs, contents of vesicles, pus- 

 tules, &c., formed in various diseases of 

 the skin, usually consist of epidermic cells 

 alone, more or less flattened or otherwise 

 altered ; or of these with the ordinary pro- 

 ducts of inflammation. Granules of soot are 

 frequently found, in London at least, mixed 

 with the above elements. Fungi exist in the 

 crusts of some skin diseases, as FAVUS, &c. 

 The fungi discovered (?) in the pustules of 

 small-pox have become extinct. The itch- 

 insect (SARCOPTES) must not be forgotten, 

 nor DEMODEX. 



ERYNGIUM. A genus of Umbellifera 

 (Dicotyledons), a species of which, E. mari- 

 timum, known as Sea- holly, found on sandy 

 sea-shores, has a long, fleshy, underground 

 stem and branches, the wood of which is of 

 peculiar character, consisting chiefly of very 

 large pitted ducts, forming an elegant micro- 

 scopic object. (See WOOD.) 



ERYSIPHE, Hedw.fil. A genus of Peri- 

 sporacei (Ascomycetous Fungi), consisting of 

 little mildews overgrowing the leaves of 

 living plants. The mycelium is formed of 

 slender ramified filaments, which spread and 

 form an entangled web over the epidermis of 

 the infected plant, but do not appear to pe- 

 netrate into the substance, so that these 

 Fungi are not seemingly true parasites. 

 From the creeping mycelium arise numerous 

 upright, shortly-jointed filaments, the last 

 one or more of the succeeding joints of 

 which swells so as to render the erect fila- 

 ment clavate or moniliform. These expanded 

 cells become detached with the greatest 

 readiness, and when they fall upon the sup- 

 porting leaf, germinate and produce new 

 mycelium threads. In this state the Ery- 

 siphes cannot be distinguished from the genus 

 Oidium; and as this state is succeeded in 



most cases by the true conceptacle of the 

 genus Erysiphe, the Oidia (such as 0. Tuckeri, 

 the Vine-Fungus), which grow under the 

 same circumstances, but do not produce 

 conceptacles, are regarded by most authors 

 as imperfect Erysiphes. (See OIDIUM.) 

 When the mycelium of an Erysiphe is deve- 

 loped late in the year, it seldom produces 

 anything but the ovate cells (conidia), but 

 if developed early in the summer, the myce- 

 lium grows at certain points into denser 

 white patches (receptacles, Lev.), from which 

 arise the conceptacles. These are small glo 

 bular sacs, composed of a double layer of 

 cells ; from the base of the outside of the 

 sac arise a number of radiating filaments, sim- 

 ple or branched (appendicles, Lev.), while in 

 its interior are developed one or many sacs 

 (asci, sporanges, Lev.), in each of which are 

 produced eight spores. In addition to the 

 above, a third form of fruit occurs, in which 

 the conidium becomes transformed into a sac 

 (pycnidiuni) filled with minute spores. 



Leveille, in an elaborate essay on this ge- 

 nus, has subdivided it into five genera, which 

 may perhaps be better taken as subgenera, 

 and may be distinguished in the following 

 manner : 



Conceptacles with one ascus. 



Appendicles dichotomously branched . . 1. Podosphaeria. 

 floccose 2. Sphcerotheca. 



Conceptacles with many asci. 



aciculate 3. Phyllactinia. 



,, uncinate 4. Uncinula. 



dichotomously branched . . 5. Calocladia. 



floccose 6. Erysiphe. 



Podosphceria does not seem to be repre- 

 sented in Britain. 



Sphcerotheca. The Rose-mildew, E. pan- 

 nosa, Auct., belongs to this group, and is 

 distinguished from E. macularis, Wallr. (S. 

 Castagnei, J. Lev.), the Hop-mildew, by 

 the appendicles of the former being white, 

 while those of the latter are coloured. The 

 mycelium of the rose-mildew seems to be 

 the same thing as Oidium leucoconium,Desm. 

 The similar structure of the hop-mildew has 

 been described and figured (from Dr. Plom- 

 ley's drawings) in the Trans, of the Horti- 

 cultural Society. 



Phyllactinia. E. guttata, Schlecht, com- 

 mon on the hazel and other trees and large 

 shrubs, is distinguished from the other forms 

 of Phyllactinia by having a bulbous base to 

 its asci, which contain only two spores. 



Uncinula. E. adunca, Schlecht, is referred 

 here ; its distinctive character is the exist- 

 ence of four spores in each ascus. Found on 



