ALG^E. 



C 30 ] 



ALKALOIDS. 



sists simply of chlorophyll in one group, 

 forming the Chlorophyllophycete of Raben- 

 horst, as the Desmideae, Confervse, &c. 

 While in the other, it exists combined with 

 Phycocyanine, giving it a bluish tinge ; 

 these forming the Phycochroniophyceae of 

 Rabenhorst,the Cyanophyceae of Sachs, as in 

 the Oscillatoriaceae,Nostochaceae, andRivu- 

 lariaceae. Fructification varied in its details, 

 but essentially reducible to three forms : 

 1. resting spores produced from the cell- 

 contents after fertilization, either by CONJU- 

 GATION or impregnation by (2.) spermato- 

 zoids produced from the contents of other 

 cells ; 3. zoospores, 2-, 4-, or multi-ciliated 

 active gonidia, discharged from the vegeta- 

 tive cells without impregnation and ger- 

 minating directly ; in some instances these 

 conjugate (CONJUGATION). The simple 

 vegetative increase of the Unicellular forms 

 is a process essentially analogous to the 

 cell-division of the filamentous forms, but 

 results necessarily in multiplication of the 

 species. The Volvocineae are remarkable 

 for their passing the vegetative stage of 

 existence in the form of ciliated zoospores, 

 mostly collected within a gelatinous common 

 envelope, or coenobium, into a definitely 

 arranged family. See CONFERVOIDE^EJ. 



Some Algae have been found fossil. (See 

 AGATE.) 



Excluded families of Algaa : 



CBYPTOCOCCE^, Kg., containing the 

 genera Cryptococcus, Kg., Ulvina, Kg., and 

 Sphcerotilus, Kg. 



LEPTOMITEJE, Kg., containing the genera 

 Hygrocrocis, Ag., Sirocrocis, Kg., Leptomi- 

 tus, Ag., ArthromituSy Leidy, Cladophytum, 

 Leidy, Mycothamnion, Kg., Erebonema, 

 Romer, Chamcenema, Kg., Nematococcus, 

 Kg., Chioniphe, Thienemann, Moulinea, Ch. 

 Robin, Enterobryus, Leidy, JEbertno, Leidy. 



PH^ONEMEJE, containing the genera 

 Stereonema, Kg., Phceonema, Kg., Phceosi- 

 phonia, Kg. 



These consist, for the most part, of aqua- 

 tic states of MUCOBINI, or of SCHIZOMY- 

 CETES. 



BIBL. Harvey, Brit. Algce, 2nd. ed. 1849 ; 

 Phycol. Britann. ; C. Agardh, Syst. Alg. ; 

 J. Agardh, Species fyc. Algar. ; Kiitzing, 

 Phycol. generalis ; Sp. Alg. ; Tabula Phyc. ; 

 Phycol. Germ. ; Lyngbye, Hydrophytoloyia 

 Danica ; Greville, Alga Brit. ; Berkeley, 

 Crypt. Bot. p. 84; Henfrey, Elem. Bot. 

 (Masters) ; Thuret, Ann. d. "Sc. Nat. 1855 ; 

 Sf Etudes Phycologiques (Anal. d. Algues 

 marines), 1878 ; Rabenhorst, Flora Earop. 



Fig. 7. 



Algarum, 1865 ; Bornet and Thuret, Ann. 

 d. Sc. Nat. 1867, vii. p. 166 (Ann. N. Hist. 

 1867, xix. p. 35), $ Notes Algologiques, 1876; 

 Sachs, Lehrb. d. Bot. 1874; Wright, Spicil. 

 Phycolog. 1879. 



ALICULA'RIA, Corda. 

 A genus of leafy Liverworts 

 (see JUNGEBMANNIE^:), con- 

 taining one British species, 

 common on hedge-banks. 



A. scalaris=Jungermannia 

 scalaris, Schrad., J. lanceolata, 

 Eng. Bot. (fig. 7). 



Jnngerm. compressa, Hook., 

 which has stipules only on the 

 innovations, is included in this Alicularia scala- 

 genus by Fries and others. ris. immature 



BIBL. Hooker Brit. Jun- gSSP^f 

 germanmce, pi. 61 ; Sowerby, gone (magni- 

 Engl. Bot. pi. 605. "M). 



ALKALOIDS. The utility of the micro- 

 scope in distinguishing the more common 

 alkaloids from each other, has been shown 

 in an able paper by Dr. Anderson. The 

 characters consist in the crystalline form of 

 the alkaloids, and in that of their sulpho- 

 cyanides. 



The alkaloids are dissolved in dilute 

 hydrochloric acid, and the dilute solution 

 mixed, on a glass plate, with solution of 

 ammonia of moderate strength if the alka- 

 loid itself is to be examined, or with a 

 strong solution of the sulphocyanide of 

 potassium if the sulphocyanide is required, 

 and at once placed under the microscope. 

 The only precaution requisite is to avoid 

 having the solution too concentrated, as the 

 crystals are then less well-defined than if a 

 dilute solution is employed. 



The power employed should be 250 dia- 

 meters ; for if a very high power is used, the 

 form of the crystals is not so readily distin- 

 guished. 



Atropine is precipitated in the amorphous 

 state by ammonia, and not at all by the 

 sulphocyanide of potassium. 



Brucia. A salt of brucia in a sufficiently 

 dilute state, mixed with ammonia, does not 

 give an immediate precipitate ; but in the 

 course of a very short time, irregular star- 

 like groups of pointed crystals are observed, 

 as in PL 11. fig. 1 a. Sulphocyanide of potas- 

 sium produces a precipitate in tufts of ex- 

 tremely thin and feathery crystals, which 

 either radiate from a centre, or present a 

 sheaf-like appearance. The latter form, 

 however, is much better marked in the 

 crystals deposited after some hours from a 



