SPORES. 



[ 724 ] 



SPORES. 



BIBL. Berk. Br. Fl ii. pt. 2. 350 ; Fries, 

 Syst. Myc. iii. p. 435, Sum. Veg. 594 ; Var- 

 ley, Tr. Mic. Soc. iii. ; Colin, Nova Acta, 

 xxv. 299 ; Berk, and Broome, Ann. N. H. 

 2. v. 460 ; Cienkowski, Bot. Zeit. xiii. 801 ; 

 Braun, Akj. Unicell 105. 



SPORES, SPOBULES, SPOBIDIA, SPOBI- 



DIOLA, MlCBOSPOBES, MACBOSPOBES, &C. 



A number of nearly connected terms which 

 are applied to the various organs which 

 either really or apparently represent, in the 

 Flowerless Plants, the seeds of the Flower- 

 ing classes. The names have been mostly 

 applied with the 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 being superseded by the more definite no- 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 : are- 

 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 

 Marsileaceae and the Lycopodiaceae, produce 

 two kinds of spore one destined to produce 

 sperinatozoids, the other archegonia and 

 ultimately embryos growing up into new 

 plants. These are sometimes distinguished 

 as pollen-spores and ovule-spores or oospores ; 

 the latter are large sacs with complicated 

 outer membranes, the former simple cells 

 with a double coat, like pollen-grains (see 



PlLULABIA, ISOETES, and LiYCOPODIACEJE). 



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. 232- 

 236, p. 321), and split up into elastic fila- 

 ments or elaters in the latter (fig. 205, 

 p. 300). In germinating, this spore pro- 

 duces a kind of thallus, the prothallium 

 (figs. 236-239, p. 321), on which antheridia 

 and archegonia ultimately appear, and an 

 embryo is formed, fertilized, and developed 

 (see FEBNS and EQUISETACEJE). 



Fig. 680. 



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, consisting of a cell 

 with a single or (generally) double coat, like 

 a pollen-grain. The spores, unlike those 

 above-mentioned, are formed in sporanges 

 which are the product of fertilized arche- 

 gonia, and more resemble the fruits of 

 Flowering plants. The spores of Mosses 

 germinate by emitting the inner coat as a 

 Confervoid filament (fig. 680), which usually 

 branches and gives 

 origin to numerous 

 stem-buds. The 

 spores of the Liver- 

 worts exhibit many 

 modifications in the 

 first stages of ger- 

 mination, as illus- 

 trated by the ac- 

 companying figures Spores of a moss germinating. 

 (figs. 682-684); Magn. 100 diams. 



the Marchantiae 



and other frondose kinds grow at once into 



thalloid fronds (see MOSSES and HEPA- 



TICJE). 



The systematic position of the Characeae 

 is perhaps still an open question ; but there 

 can be little doubt of the analogies between 

 these red productive bo'dies and those of the 

 other Cryptogamia. There is no sporange 

 here, nor apparently any archegonia. The 

 glolule^ (figs._ 121 & 122, p. 162) produces 

 antheridia giving birth to spermatozoids. 

 The nucule (fig. 120, p. 161) appears to be 

 a spore (see CHABACEJE). 



In the Lichens, only one kind of organ 

 has been termed a spore, namely the repro- 

 ductive cells formed in the thecae (PI. 37. 

 figs. 6 & 12), which are known to reproduce 

 the plant when thrown off by the parent. 

 Two other kinds of body connected with 

 the reproduction occur ; these, the gonidia 

 (PL 37. figs. 2, 3) and the spermatia (see 

 LICHENS), have fortunately obtained and 

 preserved distinctive appellations. The 

 spores are simple cells or septate tubes, 

 with a double membrane. 



In the Algae much confusion still exists, 

 not only between different kinds of spore, 

 but even between spores and sporanges; 

 and this is not easily cleared away, since in 

 certain cases the organs appear really capable 

 of serving as one or the other, according 

 to circumstances; the true spores are 



