924 
CRYPTOGAMIA. 
Class XXIV. 
Order?. ALG^. 
Reproductive organs of two kinds. 1. Thecce or tubercles variously situated. 2. Spwules or granules naked or 
immersed in the frond. Plants always aquatic and submersed. 
This order is constituted of the sea-weeds of our ocean, and of the floating scum-like substances of our ditches 
and rivers. Little is known of the functions which what are called their reproductive organs perform. The 
nature and structure of those organs are so various as to render it improbable that they should all be destined 
for the same purposes. The bodies which are called sporules are variously situated ; now filling distinct thecse (a), 
or even tubercles (.6), which are either free {b, c, d), or imbedded in the substance of the frond («?,/,) ; now ap- 
pearing to be naked and surrounded by an involucre (g) ; now scattered or arranged in some determinate 
manner in the interior of the frond. (/«) The fronds are either cylindrical (k), or plane {i), sometimes little more 
more than a mere membrane, sometimes hard and horny, and extended to the length of many feet. Many are 
articulated (i, k) : their hue of separation is then called a joint, and the space between two joints an articulation. 
Professor Agardh, of Lund, one of the most celebrated of modern cryptogamists, and whose disposition of 
AlgJE is adopted here, in his latest work, called Systema Algarum, published at Lund, in 1S24, defines the order 
thus : 
" Aquatic plants destitute of cotyledons and of sexual organs ; gelatinous, membranous, or coriaceous ; 
filamentous, laminose, or even leafy ; in color green, purple, or olivaceous; jointed or continuous; bearing 
sporidia" (little transparent bodies containing sporules), " either included in pericarps or scattered over tlie 
surface." 
The Algffi form one of the three forms of the lowest order of vegetation, Lichens and Fungi the two other. 
Of the former, many are considered by some botanists to be animalcula, and others, to be the young seedling 
plants of mosses. 
Tribe L DIATOME^. 
Bodies of various forms^flat and crystalline^ and separating into fragments. 
2259. Achnanthes. Frond stalked, vexilliform. Marine. 
2260. Diatoma. Filam.ents jointed, hyaline, rigid, simple, united in pairs longitudinally, at length separating 
into articulations cohering by their alternate angles. 
226L Fragillaria. Filaments jointed, simple, gelatinous, compressed, fragile, separating at the joints. 
2262. Mctoseira. Filaments jointed, contracted at the joints, very fragile, and easily separating. 
2263. Desmidium. Filaments transversely and densely striated, mucous, flexible, green, half separated into 
articulations, and in that state pinnatifld. 
2264. Schizoncema. Filaments bead-like, composed of narrower cohering filaments inclosing elliptical 
granules, into which they are finally dissolved. Marine. 
Tribe IL NOSTOCHIN.E. 
Individuals numerous, globular or filiform, suspended in a gelatine of a definite form. 
2265 Palmella. Minute or small, somewhat diaphanous gelatinous plants, filled with solitary granules 
unmixed with filaments. 
2266. Echinella. A roundish gelatine crammed with elliptical radiant corpuscles. Marshy. 
2267. Alcyonidium. A spongy fleshy lobed frond filled with granules. Marine. 
2268. Nostoc. Plants roundish or shapeless, gelatinous. Substance composed of curved moniliform simpk 
filaments, lying irregularly in a gelatinous nidus. 
2269. Corynephora. A gelatinous roundish puckered frond filled with jointed filaments, bearing here and 
there clavate processes. 
2270. Rivularia. A gelatinous subglobose frond filled with filaments, radiating from a ccmmon centre, con- 
tinuous, placed on a globule, and marked with annulations inside. 
2271. Chcetophora. Plant elongated or globose gelatinous. Substance composed of branched articulated 
filaments. 
2272. Scythymenia. A coriaceous tough stratum, formed of fibres and granules mingled together. 
Tribe IIL CONFERVOIDE.^. 
Filaments jointed either externally or internally, separate, and not combiyied in any definite form. 
2273. Byssocladium. Filaments like cobwebs, scattered externally with sporidia. Slightly inundated. 
22ii. Mycinema. Filaments membranous, opaque, tenacious, colored (usually tawny). Slightly inundated. 
2275. Chroolepus. Filaments rigid, nearly solid, opaque, crumbling into powder, torulose. On rocks or bark. 
2276. I'rentepohlia. Filaments flexible, colored, bearing capsules, which generally proceed from the last 
articulation, which is inflated. Inundated or fluviatile. 
2277. Scytonema. Plant not gelatinous, coriaceous Filaments short, forming dark dense tufts, beaded 
internally, or filled with annular transverse bodies. On rocks or inundated, rarely marine. 
2278. Stigonema. Filaments continuous, coriaceous, naked, marked inside with dots disposed in rings. On 
rocks. 
2279. Protonema. Filaments somewhat jointed, rooting very minute. 
2280. Hygrocrocis. Filaments hyaline, arachnoid, obsoletely articulated, floating in a shapeless gelatine or 
in a colored membrane. 
2281. Leptomitus. Filaments hyaline or slightly colored, arachnoid, obsoletely articulated, separate, erect, 
not entangled. 
