[ 327 ] 



FLORIDE^E. 



Red or colourless albuminous crystalloids 

 are found in some of the Floridese. 



Three kinds of reproductive structures 

 occur in these plants, viz. : 1, tetraspores ; 

 2, spores ; 3, spermatozoids or antherozoids. 



The tetraspores or tetragonidia. These 

 structures are of similar organization 

 throughout the order. They consist of an 



Fig. 248. 



Bhynchococcus coronopifolius. 



Section of the frond with tetraspores. 



Magnified 200 diameters. 



oblong or globular external cell or sac (peri- 

 spore), at first filled with granular contents, 



Fig. 249. 



Ptilota plnmosa. 



Section of frond with tetrasporea. 

 Magnified 200 diameters. 



which contents subsequently separate into 

 four portions, called sporules, either by 

 three transverse fissures (fig. 248) ; by two 

 fissures at right angles, cutting them into 

 quarters like an orange ; or by tri-radiate 

 fissures which part them into the 'tetra- 

 hedral' group (fig. 249) so often found in 

 the division of spore- and nollen-cells : the 

 last two occur in the spherical tetraspores. 

 The tetraspores are rarely found collected in 

 any capsular structure ; but in the Corallines 



Hildenbrant san- 



(fig. 141), and in some few foreign genera, 

 they are grouped in hol- 

 low cases (conccptacles, 

 fig. 250). In many in- 

 stances, however, they are 

 found in pod-like bodies 

 (stichidia, PL 4. fig. 13 6), 

 either formed by meta- 

 morphosis of portions of 

 the lobes or lobules of the 

 frond (Plocamiuni) , or 

 arising independently on 

 it. In others the tetra- 

 spores are naked (CaUi- gectionofaconeep _ 

 mammon), scattered over ta cle containing tetra- 

 the sides or fixed at the tips spores, 

 of the branches. In the Magn< 50 ^ am9 ' 

 majority of cases, however, these bodies are 

 immersed in the substance of the lobes or 

 lobules, not evident externally except by 

 the darker colour of the frond at the point 

 where they are collected; a lens is then 

 required for their detection ; they here 

 appear to be formed either of the cells of 

 the surface or of others immediately sub- 

 jacent. Harvey, Thwaites, Pringsheim, and 

 others regard these bodies as gemmules or 

 gonidia-, Decaisne, J. Agardh, and other 

 Algologists regard them as true spores. 

 Pringsheim states that in Ceramium they 

 grow up at once into a thallus. 



The true spores are simpler structures 

 than the tetraspores, but mostly occupy a 

 more important position. They are never 

 scattered through the frond, but always 

 grouped in definite masses, generally enclosed 

 in a special capsule, conceptacle or cystocarp, 

 which is furnished with a closed tube or 

 trichogyne (PL 4. fig. 12 c). In fertilization, 

 the spermatozoids conjugate with the tricLo- 

 gyne (PL 4. fig. 12 a). Its basal cell then 

 subdivides, the new cells forming a sporife- 

 rous heap ; as in Nemaleon (and Batracho- 

 spermum). Or, the trichogyne-cell' takes 

 no direct part in the formation of the spores, 

 which are produced after fertilization in 

 laterally arising new cells, as in the Cera- 

 miaceae &c. In Dudresnaya the elongated 

 trichogyne is spiral at the' base. After its 

 fertilization, cells sprout from beneath it, 

 and elongate to form connecting tubes, 

 These pass over the ends of the fructiferous 

 branches, which are short with an enlarged 

 terminal cell, becoming soldered with them 

 at the points of contact, the contents being 

 mixed : each connecting tube conjugates 

 with several of the fertile branches. 



The simplest form of the spore-fruit con- 



