EQUISETACE^. 



[ 243 ] 



ERVILIA. 



turn ; the end-cell grows on and multiplies in 

 both directions, until a lobulated prothalhum 

 is produced; on this arise archegonia and 

 antheridia (on distinct individuals), resem- 

 bling in all essential respects those produced 

 on the corresponding structm-e in the Ferns. 

 After the fertilization of an arcliegonium, 

 the germ-cell contained in it becomes deve- 

 loped as an embryo, and a new Equisetum 

 stem of the ordinary structm-e springs up 

 (fig. 210), forming a creeping rhizome with 



Fig. 210. 



Equisetum arvense. 



Young stem arising from a prothallium. 



Magnified 15 diameters. 



upright fistular shafts, resembling the parent 

 plant from which the spores were derived. 

 The family Equisetacese is represented only 

 by a single genus in existing vegetation, 

 containing only herbaceous plants. The 

 Equisetaceae of former ages were far more 

 important as regards size. The follow- 

 ing may be given as the character of the 

 genus : — 



Equisetum, Linn. Stems erect, cylin- 

 drical, smooth, striate, fistular, ai'ticulated, 

 simple or with whorled branches (occasion- 

 ally with whorled branchlets), bearing mem- 

 branous tooth-hke leaves, connate and form- 

 ing a short erect sheath encu'cling each 

 articulation. Thecae unilocular, six or seven 

 together, adnate all round the under sur- 

 face of a peltate sporange ; the sporanges 

 aiTanged in terminal spikes or cones. Spores 

 numerous, with four filaments arising at one 

 point, coiled elastically a few^ times roimd 

 the spore, and terminating in spathulate 

 ends, — springing loose from the spore when 

 the latter is discharged. 



BiBL. Francis's British Ferns, 5th ed. 



1855; Thuret, Jnn, des Sc. nat. 3 ser. xi. 

 p. 5; MMe,^Bot. Zeit. \^ii. p. 448 (1850), 

 and x. p. 537 (1852), Linncea, xxiii. p. 545 

 (1850); Hofmeister, Vergleich. Unters. 1851, 

 Verh. k. Sachs. Akad. d. iViss. iv. p. 123 ; 

 Bischofi^, G. W., Kryptogam. Gewdchse, 

 Iheft. p. 27. pi. 3, 4, 5 (1838), Botan.Zeit. xi. 

 p. 97 (1853), transl. in Ann. des Sc. nat. 

 3 ser. xix. p. 232.; Pringsheim, Bot. Zeit. 

 xi. p. 241 (1853). 



EREBONEMA, Rom. — A supposed genus 

 of Kiitzing's family Leptomiteae. Some im- 

 perfect filamentous organism, probably be- 

 longing to a Fungus. 



BiBL. Isomer, Deutschl. Alg. ip.'iO; Kiit- 

 zing, SjJ.AIg. p. 157. 



ERETES, Wemeck. — A genus of Infuso- 

 ria, of the family Cryptomonadina. 



Char. Those of Phacelomonas with a ca- 

 rapace. 



One species : the spores of an Alga (?). 



BiBL. Wemeck, Ber. d. Berl. Akad. 1844. 



p. 377. 



ERGOT and ERGOT^TIA. See Cla- 



VICEPS. 



ERINEUM, Pers. — A supposed genus of 

 Fungi, really consisting of abnormal deve- 

 lopments of the cells of the epidermis of the 

 trees upon which they are supposed to be 

 parasitic. They occur chiefly upon the Amen- 

 tacese, Aceraceae, and Rosaceae (Apple-trees, 

 Plum-trees, &c.). 



BiBL. Fries, Syst. My col. iii. p. 521 ; 

 Berkeley in Lindley's Veg. Kingdom, art. 

 Fungales. 



ERIOSPORA, Berk. & Br.— A genus of 

 Melanconiei (Coniomycetous Fungi), de- 

 scribed {E. leucostoma) as forming minute 

 bro^Ti spots upon dead leaves of the bukush. 

 The conceptacles are globose, and collected 

 in numbers on the stroma, bm'sting by a 

 single common (white-bordered) pore to dis- 

 charge the spores (stylospores), which are 

 filiform and xery slender, and arise in fours 

 from a sporophore. Probably corresponds 

 to the genus Robergea among the Ascospo- 

 rous Fimgi. (See Coniomycetes.) 



BiBL. Berk, and Br. Ann. Nat. Hist. 

 2 ser. V. p. 455. pi. 11. fig. 1. 



ERVILIA, Duj. — A genus of Infusoria, of 

 the family Ersdlina. 



Char. Oval, compressed; carapace open 

 on one side and in front; vibratile cilia issu- 

 ing from the fissure ; a lateral pedicle at the 

 posterior end of the bod}'. Marine. 



E. legumen = Euplotes monostylus, E. 

 (PI. 23. fig. 52; b, side view). Body very 

 transparent, exhibiting vacuoles ; length 



r2 



