DORYANTHES 



304 



DOUBLE 



D. Psilu'rus (bald-tailed). Green. Congo. 1905. 

 ., riedelia'na (Riedelian). See D. ARIFOLIA. 

 ,, tubici'na (trumpet). June. Peru. 1817. 

 ,, urceola'ta (urn-shaped). Green. Brazil. 

 Wcdle'ri (Waller's), i. Green. Floral receptacle 

 5-tailed. Nyasaland. 1893. 



DORYA'NTHES. (From doru, a spear, and anthos, a 

 flower ; the flower-stem shoots up from twelve to twenty 

 feet high, like the handle of a spear, bearing flowers on 

 the top. Nat. ord. Amaryttids [Amaryllidaceae]. Linn. 

 6-Hexandria, i-Monogynia. Allied to the American 

 Aloe, but not with succulent leaves.) 



These gigantic half-lily and half-palm looking plants, 

 with their bundled fleshy roots, seem rather out of place 

 among Amaryllids. They, with their fellows, Littaea 

 and Fourcroya, can only find head-room in the loftiest 

 conservatories. Greenhouse evergreens. Suckers and 

 seeds at times ; peat and rich loam. Summer temp., 

 60 to 80 ; winter, 45 to 50. 

 D. exce'lsa (lofty). 20. Cream. July. N. S. Wales. 



1800. 

 Guilfoy'lei (Guilfoyle's). 16. Crimson. Queensland. 



1893. 



., Larki'ni (Larkin's). Queensland. 

 Palme'ri (Palmer's). 8. Dark crimson. Queensland. 

 1874. 



DORY'CNIUM. (From doru, a spear ; adopted from 

 Pliny, who applied the name to "a poisonous herb 

 wherewith they poisoned arrow-heads, darts, &c." Nat. 

 ord. Leguminous Plants [Leguminosa?]. Linn. i7-Dia- 

 delphia, 4-Decandria. Allied to Lotus and Trifolium.) 



Seeds in March ; herbaceous ones also by division ; 

 common garden-soil. 



HARDY HERBACEOUS. 

 D. herba'ceum (herbaceous), ij. White. July. S. 



Europe. 1802. 



,, ibe'ricum (Iberian). See D. LATIFOLIUM. 

 ,, intermedium (intermediate). See D. HERBACEUM. 

 latifo'lium (broad- leaved). i. White. July. Iberia. 

 1818. 



HARDY EVERGREEN. 



D. hirsu'tum (hairy). 3. Red, white. July. S. Europe. 



1683. 

 ,, inca'num (hoary). 3. Red, white. July. S. 



Europe. 1817. 



rectum (upright). 2. Red. July. S. Europe. 1640. 

 specta'bile (showy). 2. Teneriffe. Greenhouse. 

 suffrutico' sum (subshrubby). i. White. July. 



S. Europe. 1640. Half-hardy. 

 tomento'sum (woolly). See D. HIRSUTUM INCANUM. 



DORYO'PHORA DECEMLINEA'TA. The Colorado 

 Beetle, a native of the Western United States, has, on 

 several occasions, effected a landing in this country, 

 but owing to the stringent measures adopted by the 

 authorities in this country it has, as often, been exter- 

 minated. In 1877 it committed a considerable amount of 

 damage to the Potato crops. About that time an Order 

 in Council made it a penalty for any one to keep or 

 distribute live specimens. The beetle lays its eggs upon 

 the stems and leaves of the plant. The perfect beetle 

 is small, orange-yellow, with ten black lines on the wing- 

 cases, and easily recognised. The beetle and also the 

 larvae when hatched out easily get destroyed by eating 

 the leaves which have been sprayed with the Bordeaux 

 mixture or Paris green. 



DORYO'PTERIS. (From doru, a spear, and pteris, a 

 fern; spear-leaved Fern [Filices]. Linn.z^-Cryptogamia, 

 i-Filices. Now united to Pteris.) 

 D. colli'na (hill). See PTERIS PALMATA. 



cordifo'lia (heart- leaved). See PELL^EA CORPATA. 



hasta'ta (halbert-leaved). See PTERIS SAGITTIFOLIA 



HASTATA. 



,, palma'ta (hand-shaped). See PTERIS PALMATA. 

 ,, sagittifo'lia (arrow-bead-leaved). See PTERIS SAGITTI- 

 FOLIA. 

 Walli'chii (Wallich's). See PTERIS WALLICHIANA. 



DOSSI'NIA. (Named in compliment to E. P. Dossin, 

 a Belgian botanist. Nat. ord. Orchidacea?.) 



Terrestrial Orchids requiring moist stove treatment 



and to be covered with bell-glasses to preserve the beauty 

 of the foliage. 



D. marmora'ta (marbled). J. Leaves velvety olive-green 

 netted with gold. Borneo. 1862. 



,, ,, vire'scens (greenish). Leaves greener. 



Meine'rti (Meinert's). Sumatra. 1881 



DOUBLE FLOWERS. Hybridising, aided by cultiva 

 tion, gives birth to these objects of the gardener's care. 

 To the uninitiated it seems incredible that the double 

 moss rose should be a legitimate descendant from the 

 briar ; neither do the flowers of the Fair Maid of France 

 appear less impossible derivatives from those of the 

 Ranu'nculus aconitifo'lius ; nor bachelor's buttons from 

 the common buttercup ; yet so they are. Double 

 flowers, as they are properly called, are more correctly 

 discriminated as the full flower, the multiplicate flower, 

 and the proliferous flower. 



The full flower is a flower with its petals augmented 

 in number by the total transformation into them of its 

 stamens and its pistils. One-petaled flowers rarely 

 undergo this metamorphosis, but it occurs in Campanula 

 Medium, C. persicifolia, and the Chinese Primula. It is 

 very common in those having many petals, as in the 

 carnation, ranunculus, rose, and poppy. But this is not 

 the only mode in which a flower becomes full, for in the 

 columbine (Aquile'gia) it is effected in three different 

 ways, viz. by the multiplication of petals to the ex- 

 clusion of the nectaries ; by the multiplication of the 

 nectaries to the exclusion of the petals ; and by the 

 multiplication of the nectaries whilst the usual petals 

 remain. Radiated flowers, such as the sunflower, dahlia, 

 anthemis, and others, become full by the conversion of 

 the bell-shaped florets of the disk into strap-shaped and 

 flat ones like those of the ray. On the contrary, various 

 varieties of the daisy become full by the elongation of 

 the florets of the disk, and as such flowers are tubular they 

 are described as quilled. Examples are met with in the 

 quilled China Aster, Chrysanthemum Parthenium or 

 feverfew, show Dahlias, double Scabious, the variety of 

 Gaillardia named lorenziana, &c. 



The multiplicate flower has its petals increased by the 

 conversion of a portion of its stamens, or of its calyx. 

 It occurs most frequently in polypetalous flowers. 

 Linnaeus gives an instance of the conversion of the calyx 

 into petals, and these are to be observed in the Carnation 

 (Dia'nthus Caryophy'llus). The hose-in-hose polyanthus 

 is another instance. 



A proliferous flower has another flower or a shoot pro- 

 duced from it, as in the variety of the daisy popularly 

 known as the Hen-and-chickens. It occurs also more 

 rarely in the ranunculus, pink, rose, marigold, and 

 hawkweed. A leafly shoot often appears in the bosom 

 of the double-blossomed cherry, anemone, and rose. 



A due supply of moisture, but rather less than the 

 plant most delights in, when the production of seed is 

 the desired object, a superabundant supply of decom- 

 posing organic matter to its roots, and an exposure to 

 the greatest possible degree of sunlight, are the means 

 successfully employed to promote excessive development 

 of the petals which characterise double flowers. 



By these means a greater quantity of sap is supplied 

 to the flower than the natural extent of the petals can 

 elaborate ; and those parts required for the extra elabora- 

 tion are developed at the expense of those not demanded 

 for the purpose. 



The most certain and practical method of producing 

 or obtaining double flowers is to save seed from those 

 showing an extra number of petals, or to use pollen from 

 such flowers to fertilise others, or to self-fertilise the 

 pistil of the same flower. The progeny giving the greatest 

 number of petals should be selected for further experi- 

 ment in the same way. When once a double or partly 

 double flower reproduces itself from seed, it is susceptible 

 of further improvement. 



In double flowers, as was observed by the late Sir 

 J. E. Smith, the corolla is much more durable than in 

 single ones of the same species, as anemones and poppies, 

 because, as he conceived, in such double flowers the 

 natural function not being performed, the vital principle 

 of their corolla is not so soon exhausted. Advantage 

 may be taken of this to prolong the duration of flowers 

 by cutting away the pistils or stamens, whichever 

 are least conspicuous, with a sharp pair of pointed 

 scissors. 



