SPORES. 



[ 605 ] 



SPORES. 



stylospores, like some of those of the Ure- 

 dinei, which after a stage of rest produce an 

 intermechate mycehal structure, and then 

 give birth to the ripe spores. 



The most remarkable point about this fly- 

 fungus, to which, however, Cohn does not 

 allude, is the circumstance that when the 

 body of the fly with the rings of fungi freshly- 

 developed, is placed in water, AcHLYA^ro- 

 lifera is almost always, if not always, pro- 

 duced, and apparently from the filaments 

 which in the air produce the bell- shaped, 

 deciduous body above described. We find 

 the Achlya with its ciliated zoospores, and, 

 later, with its globular sporanges filled with 

 spores, apparently representing an aquatic 

 form of the Sporendonema or Empusina. 



Several points require yet to be cleared 

 up, especially the ultimate history of the 

 spore-like body of the Emjmsina-form ; and 

 the relation between this plant and the 

 Achlya are not quite demonstrated, 



A. Braun has detected another species on 

 the gnat {Culex pipiens). 



Sporendonema Casei, Desm., is referable 



to TORULA. 



BiBL. Berk. Brit. Flora, ii. pt. 2. p. 350; 

 Fries, Syst. Myc. iii. p. 43b, Summa Veget. 

 p. 494; Varley, Trans. Mic. Soc. Loud, iii.; 

 Cohn, J<Iova Acta, xxv. p. 299 ; Berk, and 

 Broome, Ann. Nat. Hist. 2nd ser. v. p. 460. 



SPORES, Sporules, Sporidia, and 

 Sporidiola. — A number of nearlv con- 

 nected terms are applied to the various or- 

 gans which either really or apparently repre- 

 sent, in the Flowerless Plants, the seeds of 

 the Flowering classes. The names have 

 been mostly applied with a view of marking 

 slight distinctions between organs supposed 

 to be homologous. Of those placed at the 

 head of this article, the first only should be 

 retained, the second being merely a useless 

 diminutive of it, and the third and fourth 

 being superseded by the more definite no- 

 menclature now applied to the reproductive 

 bodies of the Cryptogamia. 



It may be desirable perhaps here, if merely 

 for the sake of explaining the exact meaning 

 of words constantly used in this work, to 

 pass in review the various structures com- 

 prehended under the general name of Spore. 



The definition of the word spore itself, as 

 commonly used, may be stated thus : — a re- 

 productive body, thrown off" by a Flowerless 

 plant to reproduce its kind, and containing 

 no embryo at the moment when cast off by 

 the parent. It is evident from this how lax 

 is its application. 



The highest of the Flowerless plants, the 

 Marsileacese and the Lycopodiacese, produce 

 two kinds of spore, one destined to produce 

 spermatozoids, the other archegonia and 

 ultimately embryos growing up into new^ 

 plants. These are now sometimes distin- 

 guished as pollen- spores and ovule-spores or 

 oospores ; the latter are large sacs with com- 

 plicated outer membranes, the former simple 

 cells with a double coat, like pollen-grains 

 (see PiLULARiA, IsoETES, and Lycopo- 



DIACE^). 



The Ferns and the Equisetaceae produce 

 only one kind of spore, a simple cell with a 

 double coat, the outer of which is generally 

 elegantly marked in the former (figs. 236- 

 239, p. 261), and is split up into elastic fila- 

 ments in the latter (fig. 209, p. 242). In 

 germinating, this spore produces a kind of 

 thaUus (figs. 240-3, p. 262), on which an- 

 theritha and archegonia ultimately appear, 

 and an embryo is formed, fertilized, and de- 

 veloped (see Ferns and Equisetace^). 



In the above cases the spores are always 

 formed in sporanges of various kinds, deve- 

 loped directly from the axis or the leaves by 

 a process of vegetative growth. 



In the Mosses and Liverworts the spores 

 are mostly of one kind (an obscurity exists 

 as to the nature of the difference between 

 the two kinds in Sphagnace^), consisting 

 of a cell with a single or (generally) double 

 coat, like a pollen-grain. The spores, unlike 

 those above-mentioned, are formed in spo- 

 ranges which are the product of fertilized 

 archegonia, and more resemble the fruits of 



Flowering 

 germinate 



a 



The 



emittmg 



spores 



the 



(fig 



of Mosses 



inner coat as 



685), which 



Fig. C^Sb. 



plants 



by 

 Confervoid filament 

 usually branches 

 and gives origin to 

 numerous stem- 

 buds. The spores 

 of the Liverworts 

 exhibit many modi- 

 fications in the first 

 stages of germina- 

 tion, as is illustrated ^P*^'"^^ ^^ ^ "^^^^ germinating. 

 by the accompany- Magn. loo diams. 



ing figures (figs. 686-688); the Marchan- 

 tiacese and other frondose kinds grow at 

 once into thalloid fronds (see Mosses and 

 Hepaticace^). 



The systematic position of the Characeae 

 is perhaps still an open question, but there 

 can be little doubt of the analogies between 

 these reproductive bodies and those of the 

 other Cryptogamia. There is no sporange 



,^3> 



