1362 



PLACEA 



PLANTAGO 



side, and is kept at 37 or 40 F. at night, and leave 

 them alone. They go to rest about August and push 

 up about December, flowering in May. In a pot they 

 ought to have their exact time of rest, and must be 

 buried" in the soil, which ought to be very rich, but in 

 pots they are not certain to flower. They must be 

 planted with at least an inch of soil over their necks, 

 and they prefer a loose soil. I use thoroughly decom- 

 posed cow manure (three and four years old), mixed 

 during decomposition with one-third silver sand." 



Generic characters: perianth funnel-shaped, with 

 scarcely any tube ; corona funnel-shaped, inserted at the 

 base of the segments, deeply cut, the divisions notched, 

 stamens inserted inside the corona: ovary top-shaped, 

 3-celled; ovules many, superposed: style declinate: 

 stigma capitate, obscurely 3-lobed. 



ornata, Miers. Bulb 1 in. thick: Ivs. 2, linear, appear- 

 ing with the fls.: scape 6-9 in. high: umbel 4-6-fld.: 

 perianth-segments 1-1% in. long. B.R. 27:50. Gn. 

 54:1202. 



P. grandiflbra, Lena., is thrice as big nsP. ornata, more flor- 

 iferous, and is essentially distinguished by its perianth-seg- 

 ments, which are more acuminate and sharp- pointed. I.H. 

 15:574. F.S. 20:2047 (erroneously as P. ornata). w. jyj. 



PLAGIANTHUS (Greek, obliqtie flower). Malvacece. 

 About 11 species of tender shrubs and herbs from Aus- 

 tralia, New Zealand and Van Dieman's Land, with large 

 or small white 5-petaled flowers. They are hardy in the 

 most favored parts of England. The finest species is 

 P. Lyalli, which, however, is not easily prop, by cut- 

 tings. This species is grown as a pot plant or for 

 cutting. The house treatment given Daphne will suit 

 it well. None of the species is offered in America. 

 They are known as "Ribbon Trees." 



Generic characters: Bractlets none or distant from 

 the calyx: calyx 5-toothed or cut ; column of stamens 

 divided at the apex into many filaments : cells of ovary 

 2-5, rarely 1 or many: ovules solitary, pendulous; car- 

 pels in a single series : style-branches longitudinally 

 stigmatose within. Foliage and inflorescence various. 

 Distinguished from Abutilon by the number of ovules. 



A. Fls. large, 1-1% *w. across. 



Itfalli, Hook. Small branching tree, 20-30 ft. high: 

 Ivs. 2-4 in. long, cordate-ovate, doubly crenate, pale or 

 white beneath; petiole 1-1% in. long: fls. 1-1% in. 

 across, numerous, drooping, in axillary clusters of 3-5; 

 styles pink; calyx campanulate. July. B.M. 5935. Gn. 

 44:917. G.C. III. 4:209. Said to be evergreen below 

 3,000 ft. in New Zealand, deciduous above. 



AA. Fls. small, % in. across or less. 



Lampenii, Booth. Botanically only a variety of P. 

 pulchellus, but horticulturally incomparably superior. 

 Shrub, attaining 6-8 ft. : Ivs. oblong-lanceolate, 4-5 x 

 %-l in., sharply serrate: fls. in short, axillary leafy 

 panicles, very numerous and crowded ; styles very 

 small. Van Dieman's Land. G.C. II. 22:201. 



pulchellus. Gray (Abutilon pulche'llum, Sweet. A. 

 piilchrum, Don). Tall shrub: Ivs. lanceolate, cordate, 

 acuminate, 2-3 in. long, coarsely crenate: fls. few, 

 clustered along rachis of axillary racemes: ovary 

 5-celled. Australia. B.M. 2753 (Sida pulchella). 



H. A. SIEBRECHT and W. M. 



PLAGIOBOTHRYS (Greek, plagios, sideways, and 

 bothros, pit or hollow; wherefore the name should have 

 been written PlagiobotTirus ). Borraginacece. Nine spe- 

 cies of low-growing, commonly diffuse annuals from 

 western America, with small white fls. Here belongs P. 

 nothofiilvus, Gray, which was once advertised by Breck 

 under its synonym JSritrichium nothofulvum, Gray. 

 This plant has no horticultural standing and is no 

 longer advertised. See Gray's Syn. Flora of N. Amer. 



PLANERA (after J. J. Planer (1743-1789), professor 

 of medicine at Erfurt; author of several books on bot- 

 any). Urticacew. WATER ELM. Monotypic genus, allied 

 to Ulmus and Celtis: Ivs. pinnately veined, alternate: 

 fls. polygamous, with deeply 4-5-lobed calyx; staminate 

 fls. short-stalked, in clusters at the base of the young 



branchlets, with 4-5 stamens ; pistillate or perfect ones 

 on rather slender stalks, 1-3 in the axils of .the lower 

 Ivs. : fr. a small muricate nut. The only species is P. 

 aquatica, Gmel. (Andnymus aqudticus, Walt. P. uhn-i- 

 fdlia, Michx.). Small tree, sometimes to 40 ft.: Ivs. 

 short-petioled, somewhat unequal at the base, ovate to 

 ovate-oblong, unequally serrate, glabrous at length and 

 somewhat leathery, l%-2% in. long; fr. oval, % in. 

 long, with irregularly crested fleshy ribs. April, May. 

 S. 111. and Ky. to Fla. and Tex. S.S. 7:316. This tree 

 is not in general cultivation and has little to recom- 

 mend it as. an ornamental plant. It would not prove 

 hardy north. It will probably thrive best in moist soil 

 and be prop, by seeds sown soon after ripening in May 

 and by layers. The plants sometimes cult, under the 

 name of P. aquatica belong either to Ulmus campestris, 

 var. viminalis, U. Cliinensis, or U. alata, to which the 

 true Planera is similar in foliage, or to some other small- 

 leaved elm. 



P. acuminata, Lindl.=Zelkowa Keaki. P. carpinifolia, Wats. 

 =Zelkowa carpinifolia. P. Japonica, var. Verschaffelti, Hort. 

 =Zelkowa Japonica, var. Verschaffelti. P. Keaki, C. Koch= 

 Zelkowa Keaki. P. repens, Hort.=Ulmus pumilaor Chinensis. 

 P. Richardi, Michx.=Zelkowa carpinifolia. 



ALFRED REHDER. 



PLANE -THEE. See Platanus. 



PLANER- TREE. Planera. 



PLANT (Latin, planta). A plant is a living organism 

 consisting of one or more cells, some of which, in most of 

 the higherforms, contain agreen substance chlorophyll 

 by the aid of which they are able in the light to con- 

 struct carbohydrate food-matters (as sugar, starch, etc.) 

 from carbon dioxid and water. The cell protoplasm 

 assimilates or uses these carbohydrates and is nour- 

 ished by them, and from the elements they furnish it 

 is able to make cellulose, the substance which walls 

 it in, and gives strength and solidity to the plant. 

 Animals do not (as a rule, at least) have chlorophyll, 

 and cannot construct carbohydrates from carbon dioxid 

 and water. Some plants have the habit of absorb- 

 ing their carbohydrates ready-made from other organ- 

 isms, and they are destitute of chlorophyll, as in case 

 of the fungi, lichens, bacteria, and some flowering 

 plants (e. g., dodder, Indian pipe, beech drops, etc.). 

 Such plants are more or less degenerated, and are phys- 

 iologically like animals, but they still retain enough of 

 the typical plant structure so that we are rarely at a 

 loss where to place them. Green plants absorb carbon 

 dioxid from the air, and in the process of carbohydrate 

 formation they give off a certain quantity of oxygen. 

 However, in the further chemical activities of their cells 

 oxygen is absorbed and carbon dioxid is given off. In 

 the plants which are not green (and in animals, also) the 

 first process is wanting, while the second takes place. 

 These facts have given rise to the view that plants and 

 animals are quite opposite in their physiological rela- 

 tions to the surrounding air. They should not be con- 

 trasted, however, in this way; it is more exact to say that 

 green plants have two important nutritive functions, 

 namely (1) carbon absorption and fixation (technically, 

 photosynthesis), and (2) the assimilation of food mat- 

 ters. Respiration in the process of which oxygen is 

 absorbed and carbon dioxid is given off occurs in all 

 plants and animals. C- E> BESSEY. 



PLANTAGO (the Latin name) comprises some 200 or 

 more species of annual or perennial herbs or subshrubs 

 occurring in many parts of the world. It is a weedy 

 genus, and only two or three species have any economic 

 or commercial value worth mentioning. They are gen- 

 erally known as Plantains, although this name is also 

 applied to certain bananas (see Musa) , which are plants 

 of widely different kind. Plantago lanceolata, or Rib- 

 wort, is sometimes used in pasture mixtures abroad, be- 

 cause it affords more or less spring pasturage on dry 

 and sterile soils. The seed is offered by American 

 seedsmen for feeding birds, but not for sowing. In 

 this country, however, it is one of the vilest of lawn 

 weeds, thriving in our hot, dry soils when grass kills 

 out. The only remedy for it is to secure a better stand ' 

 of grass, and this is made possible by making the ground 



