128 



arrangt'ineiit <il the sjidraunia on tlic Iroiuls is varicms. In xmic cases, as in I}<i^i/a 

 elet/ana, they are litnitetl to particular portions of the I'mnd, Ixirne on nioilitied, 

 lateral pod-like hranches, so-called sticliidia, tin- terminal ((lis of which nive rise 

 to sporanuia. In others, as in Pol;/siphonift, they are dexcloped intei'naily, within 

 the superficial cells, and are eitiier isolated or collected in wart-like masses, iicuia- 

 thecid. The latter method seems to prevail among the genera, 'i'lie fronds hear- 

 ing the tetrasjxires are. with few exceptions, dislincl from those hearing sexual 

 fruit or cystocarps. Occasionally l)o'th tetraspores and cyst(K'ar[)s are found on 

 the same specimen, as in certain species of QtllitlKunnion and Spi/ridta. '1 he 

 tetras[)oric plants are decidedly more ahnndant thiin tlie cystocar])ic. In certain 

 genera, among which Callillunnuioii, it is not uncommon to tind imtlieridia, cijMo- 

 curpx and tt'tru.<p(>reti on the same individual, a tiling rart ly to l>e seen in the 

 Florided'. lint the most pii/.zling part of the wlnde life iiislory of tlie order is the 

 complicated jirocess of sexual rej>r()dui'ti()n. In many cases the full develoi)ment 

 of the cystocarp is unknown. Many details connected with the act of fertilization 

 are as yet very ohstiire. To account for all stages from procaip to cystocarp is at 

 |)resent a prohlein of extreme interest among algologists. 



The organs of sexua! reproduction include the autiieridiiim and the pincarp. 

 the latter comprising the triclioplinre and the Iri'liof/i/iie. Asa rule, the sexual cells 

 are terminal in jiosition and more or less fixed, usually pl:ice(l on the youngest 

 lateral hranclu's of the frond, and are either unicellular or multicellular, thus 

 forming clusters. 



A hrief docripiion of tiie simplest arrangement to ellect fertili/.ali(ni i-ihe 

 following : 



The terminal cidls of two lateral liranches liecome changed in form and 

 structure; the one. tuft-like, the aniherid, contains a simple uon-inolile. non- 

 ciliated autherozoid ; the other, a terminal cell, with two helow l'(n-ming the 

 procarp, enlarges and elongates alxtve to form a long, slender, hyaline hair, the 

 /ricliofjyne, whose basal portion is the lrirli"p/io'r. In the simples'l t'orins, as in the 

 Bangiaceii; the antlierozoids eoine in contact with the extremity of the ri'ce]itive 

 trichogyne where they adhere for a time, .\fter the walls of hoth ])(dnts in con- 

 tact are alisorhi'd. the fertilizing intliUMice is i)ropagale'l through the tri(diogyne 

 to the trichophore, which eulargt^s by cell division. In this case the tricliophore 

 becomes the carpogenie cell, which subse(|uently divides, each iliris mi yieldiusi a 

 car|)ospore. Such a product of fertilization is a Cj/Mociirp, whose tormatioti is 

 direct. Other cases of direct formation occur, as in .\i')ii(ili()ii and Ch(tnlr(U(.<iay 

 where the c.-irpogenic ceil gi\es rise to an outgrowth of o/'iblasti-ma filaments 

 wh')-^e cystocarp- consist of (dusters of sporangia. In by far the greater number 



