NATIVE PLANTS 



NECTARINE 



2115 



tions of living had become established. People had 

 outgrown the desire to remove. They appreciated their 

 own plants and also those from the New World. Ameri- 

 can plants attracted attention in Europe rather than 

 in America. 



Twenty-five years ago, the writer made a census of 

 indigenous American plants known to have been 

 introduced to cultivation. The statistics were pub- 

 lished in ''Annals of Horticulture for 1891." It was 

 found "that there are in North America, north of Mex- 

 ico, about 10, 150 known species of native 

 plants, distributed in 1,555 genera and 

 168 families. Of these, 2,416 species are 

 recorded in this census, representing 769 

 genera and 133 families. Of this number, 

 1,929 species are now offered for sale in 

 America; 1,500 have been introduced into 

 England, of which 487 are not in cultiva- 

 tion in this country." All these species 

 are there catalogued. The only other 

 account of the entire cultivated flora is 

 that which was compiled in the "Cyclo- 

 pedia of American Horticulture," 1900- 

 1902, and for which the lists of twenty-five 

 years ago were a preparation. That Cyclopedia de- 

 scribed 2,419 species of plants native to North America 

 north of Mexico. A brief sketch of the history of recent 

 efforts toward the introduction of native plants is given 

 in the preface to the catalogue of 1891. 



Formerly, the term "American plants" had a tech- 

 nical meaning in England. William Paul in his book 

 on "American Plants," published in London in 1858, 

 writes as follows: "The history of American plants may 

 be briefly told. The term is popularly applied to several 

 genera, principally belonging to the natural order 

 Ericaceae. They are generally 'evergreen,' producing 

 their flowers for the most part in the months of May and 

 June." The book is devoted largely to rhododendrons, 

 azaleas and kalmias, although European and other 

 heaths are included. 



There is a strong tendency toward the production of 

 peculiarly American types and races even in species 

 domesticated from other countries, as of the carnation 

 and sweet pea. As American plant-breeders give greater 

 attention to native species, the divergencies between the 

 horticulture of the Old World and that of the New 

 World will be accentuated. The recent multiplication 

 of books about native plants has stimulated interest in 

 the indigenous resources. L, jj, g. 



NAUMBURGIA: Lysimachia. 



NAUTILOCALYX (apparently nautilus-shaped calyx). 

 Gesneriacese. Herbs of Trop. S. Amer., usually referred 

 to Episcea, but lately separated and re-defined by 

 Sprague (Kew Bull. 1912, 85). As now constituted, it 

 comprises species named in Episcea and Alloplectus, 

 9 being included altogether. Two of these may be 

 mentioned here, although apparently not in the Ameri- 

 can trade. The species of Nautilocalyx have the gen- 

 eral habit and appearance of Episcea, but differ in 

 having ovules on the inner surface only of the placental 

 plates rather than on both surfaces. They are distin- 

 guished from Alloplectus in being herbs rather than 

 shrubs and undershrubs, and in bearing a larger corolla- 

 limb. 



N. Fdrgetii, Sprague (Alloplectus Forgetii. Sprague). 

 Fls. pale yellow, corolla hairy outside, the calyx-segms. 

 much shorter than the corolla-tube: Ivs. with very 

 wavy margins, somewhat truncate at base, green above 

 and red along the ribs and veins beneath ; petioles 2 in. 

 or less long, villous. Peru. N. pdllidus, Sprague (Allo- 

 plectus pdllidus, Sprague). Fls. creamy white, the 

 corolla hairy outside and the front part of the tube 

 purple-striped inside and the back part with broad 

 band of purple blotches: Ivs. gradually narrowed to 



base, nearly glabrous above, minutely puberulous 

 beneath. Peru. B.M. 8519. L. jj. B. 



NECTAR. Most flowers pollinated by insects possess 

 nectar-glands, simple or composite, located upon some 

 part of the floral structures. To designate nectar by 

 its chief constituent would be simply to call it a sugar 

 solution, more or less watery or dense, depending upon 

 the flower, or upon the conditions under which pro- 

 duced. However, several sugars may be present, as well 



2452. Various forms of nectaries. Left, the nectar-spurs of Linaria vulgaris; 

 the cushion-like nectaries in a grape flower; nectaries of columbine; right, the 

 nectar-scales on petals of ranunculus. 



as small quantities of other substances. Just as in 

 honey, the predominant form is fruit-sugar, with cane- 

 sugar next in importance, and always with small 

 amounts of aromatic substances yielding the odor and 

 affecting the taste of the product. Sometimes muci- 

 laginous substances are present. Honey contains less 

 water than nectar, also other aromatic compounds and 

 small amounts of waxes and pollen. The abundant 

 secretion of nectar is, to a large extent, dependent upon 

 external conditions, and usually is favored by condi- 

 tions inducing the perfection of the flowers. 



Nectaries occur on various parts of the flowers, often 

 about the base of one or more petals, or even stamens; 

 again, they may take the form of glandular protuber- 

 ances or ridges arranged between any of the whorls 

 of floral members; while the most interesting and 

 conspicuous modifications involving the nectaries are 

 those hi which one or more of the petals or other floral 

 leaves may be changed into pockets, spurs, or recep- 

 tacles. Some of the interesting types of modification 

 may be noticed in the violet, columbine, nasturtium, 

 and certain orchids. An extreme form is found in a 

 Madagascar orchid, angrsecum, in which the nectar- 

 tube may be 6 inches long. Various nectaries are shown 

 hi Fig. 2452. In all cases, the nectar is secreted from 

 glandular cells located either superficially or more 

 deeply in the tissues, and in the latter case connected 

 with the receptacle by nectar-ducts. The secreting 

 cells may be confined to a single small spot or may be 

 spread over a larger area or zone. 



The development of the curious and complicated 

 nectaries referred to indicates a remarkable adjustment 

 for insect pollination, and whatever may be the immedi- 

 ate explanation of the development of these structures, 

 they serve a most useful purpose in effecting cross- 

 pollination. It is necessary to add, however, that the 

 secretion of sugary liquids by plants is not confined to 

 nectaries, and oftentimes the relation of these secre- 

 tions to any useful purpose is not clear. The produc- 

 tion of "honey-dew" by certain plants, normaUy or 

 through the incitation of aphid punctures, is allied to 

 nectar-secretion. The opportunities determining the 

 excretion of sugars by nectaries have been considerably 

 studied by physiologists; but, for these facts, the reader 

 must seek information in papers dealing more exten- 

 sively with the osmotic properties of cells, as the subject 

 is too technical for discussion here, g M. DUGGAR. 



NECTARINE, a smooth-skinned peach (Prunus 

 Persica var. nucipersica) . Fig. 2453. It was formerly 

 thought to be a distinct species of plant. By DeCan- 

 dolle it was called Persica Isevis. Roemer in 1847 made 



