^4 ACOTYLEDONS. AL.GJE. iVoS'lOC. 



Order III. ALGiE^ 



Vegeldbles for the most part aquatics, destitute of roots, or fur- 

 nished only with a fibrous or scutate base for tlie purpose of 

 attachment merely; \\\\o?:e J'luiich are either gelatinous, fila- 

 mentose, membranous, or coriaceous, having, for fructifica- 

 tion, seeds or sporules, either imbedded in tubercles or pro- 

 cesses arising from the frond, or immersed and more or less 

 scattered in the substance of the ^roz/c? itself. 



Many species of this singular, and, generally speaking, beautiful 

 order of plants, frequently float in the water without any point 

 of attachment to extraneous substances. They are mostly 

 subpellucid, and the cellules are often elongated and united so 

 as to form fibres interrupted by transverse dissejjimcnts. Their 

 colour is various, often green, brown, red, &c. After having 

 been kept dry for a great length of time, they will revive by 

 immersion in water, but that portion of the plant only imbibes 

 the fluid which is immersed in it. 



Div. I. Tremellin.e, Frond gelati7ious of a delermbiedjigiire, 

 containing ivit kin conj'erva-like or headed filaments. — Root 

 none. Frovd either globose or palmate, or f If or m, consist- 

 ing of a gelatinous, pellucid substance, in ivkicti are imbedded 

 clustered, conferva-like, jointed, branched, or simple fila- 

 ments. Frnctif either interior, included in the joints of the 

 filaments, or rarely exterior i?i capsules. Colour generally 

 green, sometimes brown or purplish. 



1. NOSTOC. 

 ^nlaments moniliform, composed of united globules. jF;o?7(/ oli- 

 vaceous, between gelatinous and coriaceous, bullate, hollow, 

 at length spreading, filled with moniliform, simple, curved, 

 and crisped filaments. According to Vaucher, these plants 

 propagate by the globules of which the filaments are composed, 

 which, by degrees, separate and grow into new individuals. 



1. N. commune, upon the ground, frond lobed and plicate bul- 

 late gelatinous olive green. Ag- p. 133. TremeUa Nostoc, 

 Lightf. p. SdS. E.B.t.4Q\. 



Hab. Gravelly walks and pastures after rain, frequent. Light/., Hopk. 



2. N. verrucosum, frond bladdery subcoriaceous hollow plicate 

 and smooth. Ag.p. 132. TremeUa verrucosa, Lighlf. p. 899. 



* In this order I follow and adopt the ordinal and generic characters, M'ith 

 few exceptions, of Agardfi, in his Stiiwpsis Algurum Scandlnavias, Lund, 

 1817. 



