A SYNOPSIS OF THE PLANT KINGDOM 



11 



eiuiosporous, the spore wall of the macrospores soon 

 rupturing and exposing the archegonia. 



The one genus, Selaginella, and about 500 species 

 are widely distributed, but mcsstly tropical. The 

 majority prefer damp forests, but some (e.g., .S'. rupes- 

 tris) are xerophytic. Three species are native in the 

 eastern United States. The family is related to the 

 Lycopodiaceae superficially, but not in the spores and 

 in the prothallia, which are more closely allied to 

 another family, the IsoetaceK. The habit, the foliar 

 ligule, the undifferentiated spores, and the endosporous 

 prothallia are distin(;tive. 



The spores of Selaginella have been used in the same 

 manner as those of Lyeopodium, but are less easily 

 obtainable. S. conrinmi and .S. ohlusa have been used 

 for diarrhea and dysentery. Several Mexican species 

 are used locally for medicine. S. coiwohda is employed 

 in the East Indies as an aphrodisiac. The rosette-Uke 

 iS. lepidophylla of Mexico is the best-known "resur- 

 rection plant." When dry, it rolls into a ball and 

 becomes brown; when the air is humid, the branches 

 spread out and the green upper surfaces are exposed. 



Man}- species of Selaginella are in choice American 

 collections, but very few are commonly in the trade. 

 The}' are mostly grown for greenhouse and for table 

 decoration under the name of "lyeopodium." 



SPERMATOPHYTA or SIPHONOGAMIA 

 (PHANEROGAMIA) 



SUB-DIVISION I. GYMNOSPERM^ 



Order 8. Cycadales 



15. Cycadaceae (from the genus Cycas, the Greek 

 name of a certain palm). Cycas Family. Fig. 4. More 

 or less woody plants, with thick, unbranched, columnar 

 or tuberous stem: leaves alternate, pinnate: stamens 

 and carpels borne in cones or in temporarily terminal 

 clusters: scales of the staminate cone bearing very 

 many scattered anthers on the under side; the carpels 

 open, not forming a closed o^'ary, either leaf-like pin- 

 natifid and bearing marginal ovules, or jjeltate with 2 or 

 more suspended ovules; the latter very large, often 1 

 inch long, orthotropous, with 1 integument, becoming 

 drupe-Uke. 



Cycadacea> has 9 genera and about S.5 species, dis- 

 tributed in tropical and subtropical regions. Zamia 

 is the largest genus, with 30 species. The family stands 

 isolated among the gymnosperms. The palm-like 

 habit, pinnate leaves, very numerous scattered stamens, 

 and, in Cycas, the leaf-like carpel, are distinctive. 

 Differences more important to the morphologist are to 

 be found in the embryology, especially in the fertiliza- 

 tion by motile sperm-cells. The leaves are circinate 

 when unfolding, like those of a fern. The Cycadacea 

 represent an ancient family far more numerous in past 

 geologic ages. Many fo.ssil .species are known. 



Various species of Cycas in the Moluccas and Japan, 

 especially C. revolula, yield a sago in the pithy part of 

 the stem which the natives bake into bread. The 

 fiottentots eat the pith of Encephalartos, making 

 from it "Kafir bread." The seeds of Cycas and Zamia 

 are edible. The leaves of Cycas are used at funerals 

 and church festivals as "palm branches." 



Several genera are in culti\'ation in America for 

 greenhouse use and outdoors in the South. These are 

 Bowenia; Ceratozamia of Mexico; Cyca-s (Sago Palm) of 

 the far East; Dioon of Mexico; Encephalartos of South 

 Africa; Macrozamia of AustraUa; Stangeria of South 

 Africa; Zamia (Coontie, Comptie) of tropical America. 



Order 9. Ginkgoales 



16. Ginkgoacex (from the genus GuiAjo, the Japanese 

 name;. Ginkgo Family. Fig. 4. Much-branched tree 



with deciduous leaves: secondary wood without true 

 vessels; resin-tubes present: leaves alternate, fan-shaped 

 like the pinnules of Adiantum; veins forking: anthers 

 borne in pedicelled pairs on a slender axis, withcjut 

 bracts, the whole somewhat catkin-like: no true pistil- 

 late cone; ovules borne in pairs at the summit of 

 branched peduncles, each ovule surrounded at the base 

 by a fleshy ring: fruit drupaceous. Fertilization is by 

 means of motile sperms. 



A single genus of one species occurs in China and 

 Japan. Fossil species are known. The family is dis- 

 tantly related to the ConiferiE, but the peculiar foliage, 

 as well as the absence of cone structure and the great 

 reduction of sporophylls, is distinctive. , 



Ginkgo bUoba (ginkgo, maidenhair tree, Kew tree), 

 the only species, is grown as a park tree. 



^3o 



4. CycadacE-E: 1. Cycas, a, leaf: 6, carpel with ovules: c, male 

 scale with anthers. 2. Zamia, female cone. Ginkgoace.e: 3. 

 Ginkgo, a, leaf; 6, ovules; c, stamen. 



Order 10. Conifeeales 



17. Taxaceae (from the genus Taxus, the classical 

 name, probably from the Greek meaning bow, for which 

 the wood is used). Yew Family. Fig. 5. Much-branched 

 trees or shrubs, with resin-tubes in the bark and no 

 true vessels in the secondary wood: leaves alternate, 

 needle-like or scale-like, persistent: stamens borne on 

 the protected portion of more or less apically thickened 

 or peltate scales (sporophylls) forming a small cone: 

 pistillate cones wanting; ovules borne singly or two 

 together on a fleshy or rudimentary carpel (sporophyll), 

 inverted or straight, the outer integument forming an 

 arillus: fruit a dry seed surrounded by the fleshy often 

 highly colored arillus; the receptacle also often enlarged 

 and forming a fleshy part of the fruit. 



TaxaceiE has 8 genera and about 70 species widely 

 distributed, of which 40 belong to the genus Podocarpus. 

 The family is related to the Coniferse, but differs in the 

 reduction of the pistillate cone to a single ovule, in 

 the modification or suppression of the sporophyll, and 

 in the aril or arillus. The closely related Ginkgoaceae 

 ha-s a different staminate inflorescence. Fertilization is 

 by means of pollen-tubes. 



The timber produced by the tropical eastern species 

 of Podocarpus and of Dacrydium (heron pine and 



