A SYNOPSIS OF THE PLANT KINGDOM 



eists of the the fusion of two zoospore-like gametes, or 

 the fusion of one such gamete and a specialized non- 

 motile egg. The latter condition is characteristic of 

 the higher forms in nearly all the sub-groups of the 

 Chlorophycese. The plant body in the Order Siphonales 

 is peculiar in that it consists of a continuous tube with- 

 out cross-walls. Some common genera in this class are 

 Volvox, Chlamydomonas, Pandorina, Protococcus, 

 Pediastrum, Scenedesmus, Hydrodictyon (Water-net), 

 Ulothrix, Ulva (Sea-lettuce), CEdogonium, Cladophora, 

 Caulerpa, and Vaucheria. 



CLASS X. CHARACEiE (Stoneworts) 



Attached plants (1 inch to 1 yard in length) of fresh 

 or brackish water, consisting of a slender stem, which 

 bears at each node a whorl of branches, usually again 

 bearing whorled branchlets. The internodes consist of 

 one immense multinucleated cell often as much as 

 3 inches long, which is naked or inclosed in a sheath 

 of smaller cells. The branches are similarly constructed 

 though the cells are correspondingly smaller. Asexual 

 spore-reproduction is absent. Sexual reproduction is 

 by means of an egg-cell inclosed in a jacket of spiral 

 wall-cells, and of sperm-cells inclosed in an antheridium 

 which has a multicellular wall. These sexual organs 

 are borne at the nodes of the branchlets. The fertilized 

 egg and its investment becomes a thick-walled resting 

 structure. Many species of Chara and Nitella, the 

 only two genera, have the power to deposit lime from 

 solut ion, and thus become incrusted with that substance, 

 hence the popular name. In this way the Characeae 

 have played a part in the filling up of calcareous lakes 

 and the production of new land. They are mostly in- 

 habitants of calcareous waters. 



CLASS XL PH^OPHYCEiE (Brown Seaweeds) 



A large group of salt-water algae, well known in all 

 waters of the globe, but most abundant in the colder 

 regions. Plant body attached, usually thalloid and 

 branched, but very diverse; in some cases filamentous, 

 in others disk-shaped or globular. The larger forms of 

 Laminaria are sometimes 200 feet long. The chroma- 

 tophores of the Phaeophyceae contain a brown pigment 

 which gives to these plants a brown or yellowish color 

 instead of green. The thallus is often very tough and 

 cartilaginous, to resist the waves. Zoospores are often 

 produced. In sexual reproduction, the gametes are 

 either similar and motile, rarely non-motile, or more 

 often the sperm is motile while the egg is much larger 

 and non-motile. Details of structure in respect to 

 reproduction, however, are very great. 



The thallus of various species of PhEeophycese yields 

 iodine and soda. Some species (e.g., Laminaria sac- 

 charina) yield mannite and are used in the Orient for 

 food. The dried stalks of L. digilala and L. Cloustoni 

 have been used in surgery. Fucus and other genera 

 are used as manure. 



One species, Sargassum bacciferum, has acciunulated 

 in great quantities in the Atlantic Ocean between the 

 Bermuda Islands and the Spanish coast, in the so-called 

 "Sargasso Sea." 



CLASS XIL RHODOPHYCE.E (Red Seaweeds) 



Mostly marine alga;, a few only inhabiting fresh 

 water, widely distributed, but most abundant in the 

 tropics and temperate region at lower depths. The 

 thallus is very diverse, filamentous, branched, often 

 thalloid, attached by holdfasts, and red, violet, or 

 purple in color, rarely green. True starch is not found. 

 Asexual spore-reproduction is frequent. These spores 

 are non-motile and produced in fours (tetraspores). 

 Sexual reproduction is by dissimilar gametes, the 

 antheridium becoming without change a single non- 

 motile sperm-cell. The egg-cell is prolonged upward 

 into a slender tube (trichogynej. The fertilized egg 



by division gives rise to a globular mass of short fila- 

 ments (cystocarp) which produce asexual spores. These 

 spores in turn give rise to the mature plant. The 

 cystocarp and its spores, thus following fertilization, 

 suggest the alternation of generations found in the 

 mosses and liverworts and all higher plants. About 

 300 species of Rhodophycea; have been described. 



Carragheen, or Irish moss, used in jellies and pud- 

 dings, is the dried thallus of Chondrus crispus and Gigar- 

 tina mamillosa of northwestern Europe. Agar-agar, 

 used in the preparation of culture media in bacteriology 

 and mycology, is obtained from various species of this 

 group. 



CLASS XIII. PHYCOMYCETES. 



A large group of parasitic or saprophytic organisms 

 (fungi), without chlorophyll: thallus (mycelium) of 

 much-branched filaments (hypha;); usually without 

 cross-walls (non-septate), as in the algal group Si- 

 phoneae: asexual reproduction by motile or non-motile 

 spores which are usually borne in sporangia, and by 

 conidia which are cells abstricted from the tips of 

 specialized hyphae: sexual reproduction diverse, either 

 by the conjugation of similar gametes, or by the con- 

 jugation of a specialized antheridial branch (male) and 

 an enlarged oogonial branch (female) which contains 

 the egg; free sperm-cells are rare. The order Oomy- 

 cetes, with differentiated gametes, contains the following 

 important fungi: Saprolegnia (water-mold), a whitish, 

 aquatic mold growing on decaying plants, insects, or 

 living fishes; Olpidium brassicse, parasitic in cells at the 

 base of the stem of young cabbage plants causing their 

 death; Phytophihorainfestann {pot&to disease); Plnsmo- 

 para viticola, downy or false mildew of the grape; Albugo 

 Candida, white rust of Cruciferae; Pythiumde Baryanum, 

 causing damping off of seedlings. Order Zygomycetes, 

 with similar gametes, contains Mucor mucedo, white 

 mold of bread, fruits, etc. ; Rhizopus nigricans, a mold 

 on bread, fruit, etc.; Empusa muscse, parasitic on 

 houseflies, causing their death and producing a white 

 halo about them on the surface where they die. 



CLASS XIV. EUMYCETES 



A very large and important group of saprophytic or 

 parasitic organisms (fungi) without chlorophyll: thallus 

 (mycelium) composed of fine tubular threads, which are 

 septate: sexual organs usually obscure or apparently 

 wanting: asexual reproduction by spores or by conidia, 

 a modified form of which is termed basidia. The 

 conidia and basidia do not always represent homolo- 

 gous organs. The group is divided into Ascomycetes 

 and Basidiomycetes. The Ascomycetes are character- 

 ized by a group of usually 8 spores inclosed in a unicel- 

 lular sac (ascus), which is produced immediately after 

 the imperfect sexual fertilization. The asci are borne in 

 spherical bodies (perithecia) or in open cups (apothecia). 

 The Perisporiaceae, Discomycetes, Pyrenomycetes, and 

 Tuberaceae are orders within this sub-class. Among the 

 many important economic fungi belonging here are 

 the following: Erysipheae (Downy Mildews); Aspergil- 

 lus and Penicillium (Fruit Mold, Blue Mold); Mor- 

 chella (Morel), edible; Nectria (Currant Cane Rust and 

 Tree Canker) ; Claviceps purpurea (Ergot) , parastic in the 

 ovaries of grains; Taphrina (including Exoascus), caus- 

 ing witches' broom, leaf curl of peach, plum pockets, 

 etc.; Saccharomyces (Yeast), causing fermentation 

 in saccharine solutions. The Basidiomycetes are 

 characterized by the production of four spores on a 

 special hyphal tip or thread (basidium). Each spore 

 is raised on a minute slender stalk (sterigma). These 

 spores, in some cases, if not in all, follow immediately 

 after a nuclear fusion, which probably represents a 

 reduced sexual act. In this group are the Ustilagineae 

 (Smuts), infesting the ovaries of grains, etc.; the Ure- 

 dineae (Rusts), which infest a wide variety of culti- 

 vated and wild plants, and among which may be men- 



