(i 



A SYNOPSIS (W THE PLANT KINGDOM 



tionixl the wheat rust; the llvinononiyoetos (Mush- 

 rivuns, ToadstwMs, anil Hraokot l'uii(ii), whicli are 

 sapivphylic or inhaliit tinibcr; aiul tlu' tijustcromyootes 

 l'iilT-balls\ wliii'h arV .-iapropliytic. The rusts exhibit 

 allornalion of generations to a most reniarkaUle degree, 

 theditTerent generations often iidiubiting (hITerent host 

 phmts and possessing a wholly dilTerent appearanee, as 

 well !»s a wholly dilTerent method of sporc^forniation. 

 The Hymenoniyeetes are sapro])hytic,exeept the genus 

 Exobiisidiuin whieh inhabits the living foliage of various 

 plants, the genus Arniillaria wliich infests living tree- 

 trunks, and many geni-ra of the I'olyporaceir (Bracket 

 Fimgi I whieh also attack the W(Xk1 of living tn-es. The 

 l;ist-nientioned fungi, including Arniillaria, iidiabit the 

 trunks; and bninches of forest trees, causing their death. 



CLASS XV. LICHENES (Lichens) 



Green, gra>' or highl>' colored plants of very diverse 

 habit and habitat, i-ither thalloid, fruticose or crusta- 

 ceous, and growing on the soil, bark of trees, rocks, or 

 rarely on foliage: propagation by tlivision of the thallus 

 or by the separation of special minute powdery parts 

 (.soredia): spore-reproduction by luscospores borne in 

 [)erithecia or apothecia, rarel>- bj- basidiospores. The 

 lichen thallus is not a single organi.sm, but is prob- 

 ably a symbiotic structure, <«mi)rised fundamentally 

 of fungus hyphae between which many vmicellular green 

 alga' are distributed, usually in a definite fashion. 

 The fungi belong to the Ascomycetes in the great 

 majority of cases, rarely to the Bsisidiomycetes. The 

 alga* may belong to the Chlorophycea>, in which case 

 they are unicellular, or to the Cyanophycea', in which 

 ca.se they are either unicellular or in chains. Because 

 the symbiotic structure behaves as a unit, it has been 

 decided to continue to treat the lichens as a cla.ss by 

 themselves, rather than to consider the algal and fungal 

 components independently in their respective groups. 

 Except as soil-producers, li<^hens are of little economic 

 importance: Cetraria islamticn furnishes Iceland moss; 

 Slicla pulmonaria was once used in medicine; Cladonia 

 rangiferinn furnishes the main food of the reindeer in 

 Lapland, and, possibly, of other arctic animals; Roccella 

 lincloria of Africa and the East Indies is the source of 

 the chemical indicator, litmus and of the dye orchil or 

 orseille. 



DIVISION II. BRYOPHYTA 



(Mosses and Liverworts) 



Small green plants of simple structure, either thalloid 

 or differentiated into stem and leaves: true roots 

 wanting: vascular tissue absent: alternation of gen- 

 erations well developed, the gamete-bearing generation 

 dominant : female gamete (eggj inclosed in a flask- 

 shaped multicellular archegonium: male gametes (sperm- 

 cells) inclosed within a multicellular antheridial wall: 

 fertilized egg protlucing the M|)ore-bearing generation 

 (sporogonium) which (Consists of a parasitic or semi- 

 parasitic capsule usually borne upon a seta. 



The Brj'ophytes arc divided into two great classes, 

 namely the Hepatica (Liverworts) and the Musci 

 (Mos-S**). Each of these in turn is divided into several 

 orders, which, as usual, cont.-un one or more families. 

 Mosses and liverworts are widely distributed over the 

 earth, the latter seeming to prefer limestone regions. 



The Hepatica; are characterized by a spore-bearing 

 generation consisting of a stalked or sessile simple cap- 

 sule, which contains spores and elongated sterile elaters, 

 and splits into teeth or valves at maturity. The 

 plant body (gamete-bearing generation) consists either 

 of a thalloid, algal-like, dichotomously branching, 

 ribbon-like structure, or of a slender axis bearing the 

 verv- thin leaves, one cell in thickness, and destitute 

 of a midrib. The lea\'es are usually arranged in two 

 lateral rows, with often a third row of small dissim- 



ilar leaves on the under side, so that the shoot is 

 strongly dorsi-ventral. The lateral leaves fre(iuently 

 bear at the biuse a curious lobe that is infolded or 

 even Hask-shapetl, and probably aids in the conserva- 

 tion of water on the dry rocks and tree trunks which 

 many of these plants frequent. The under side of the 

 stem or thallus is usually provided with rhizoids that 

 take the place of roots. The thalloid liverworts are 

 inhabitants of damp or wet situations, some being 

 aquatic: in the North, they are found on damp .soil, wet 

 rocks, or among damp moss. The majority of foliose 

 liverworts inhabit similar places, only comparatively 

 few genera and species being xerophytic. Filaments of 

 the alga, Nostoc, penetrate the cavities in the thallus 

 of Anthoceros and there form endophytic colonies. Veg- 

 etative reproduction is accomijlished by the branching 

 of the thallus, or by the production of special buds, 

 called genuna', either on the edge of the leaf or thal- 

 lus, or in special cup-like receptacles borne on the sur- 

 face of the thallus. 



The Hepatica; are di\'ided into four principal orders 

 as follows: Order I. — Ricciales. Thalloid, floating or 

 amphibious: sexual organs sunken in the thallus: 

 capsule sessile, thin-walled, endophytic, irregularly 

 dehiscent. Order II. — Marchantiales. Thalloid: arch- 

 egonia and antheridia usually borne on special branches 

 of the thallus: capsule often stalked, usually regularly 

 dehiscent. Marchantia was formerly used as a remedy 

 in diseases of the liver, hence the name liverwort. 

 Order III. — Anthocerotales. Thalloid: one chloroplast 

 in each cell: sexual organs superficial: capsule very 

 slender, chlorophjdl- and stomate-bearing, continuing 

 to elongate by basal growth. Order IV. — Jungerman- 

 niales. Thalloid or foliose: capsule usually splitting 

 to the ba.se into four valves. 



The Musci (Mosses) differ from the Hepatica mainly 

 in the more elaborate capsule, which in the young 

 state commonly contains chlorophyll, is provided with 

 stomates, and contains a central column of sterile 

 ti.s.sue (columella) encircled by the spore - bearing 

 chamber. The dehiscence of the capsule is apical and 

 transverse, and consists in the formation of a hd (oper- 

 culum) which falls off exposing the mouth of the an- 

 nular spore-chamber. This mouth is surrounded by a 

 single or double row of numerous hygroscopic teeth 

 (peristome), which, by their bending, regulate the 

 escape of spores in wet, and dry weather. No elaters 

 are produced. The sporogonium of the moss is, there- 

 fore, not only a more independent structure from the 

 standpoint of nutrition than is that of most hverworts, 

 but is constructed along wholly different lines. On the 

 summit of the capsule is usually found a delicate, 

 diversely shaped, hood-like cap not organically con- 

 nected with it and easily detached, called the calyptra. 

 This is the enlarged upper portion of the archegonium, 

 which, after rupture, is borne aloft on the summit of 

 the growing sporogonium. The plant-body (gamete- 

 bearing generation) is never thalloid; and the leaves, 

 which are provided with a midrib, are frequently of 

 several cells in thickness. The germination of the spore 

 does not result at once in a moss plant, but produces 

 a creeping filamentous branched, algal-like growth 

 (protoncma) on which at length are borne the buds 

 that give rise to the moss-stem proper. 



The Musci .are subdivided as follows: Order I. — 

 Sphagnales (Bog or Peat Mosses). Structure of stem 

 and leaf peculiar, consisting of dead, tracheid-like cells 

 without protoplasm and provided with pits or thicken- 

 ing bands, regularly interspersed among slender, living 

 cells containing protoplasm and chloroplastids. Lender 

 ordinary conditions, the tracheid-like cells are filled 

 in part with air, and hence the plant has a grayish 

 hue. In the presence of rain or abundant .soil-water, 

 the water is drawn into the cells bj' capillarity until 

 the still apparently dry plant contains a surprisingly 

 large quantity of water, which will flow out on stiueezing 



