Doryanthes 



( 307 ) 



Drab a 



culture in a moist stove heat. Propagation is by 

 root division in spring, before growth begins ; also 

 bv seeds sown on a hotbed in spring. Soil, equal 

 parts of loam and leaf soil, with sand. 



Principal Species: 



iirgcntata. Ivs. dark grn., with broad silvery 

 central band. 



Other Species : 

 bowiuaiiiaua, 0", Ivs. dark grn., blotched wh. 



gru., wh (*'/. maftulata). 



Contrajerva, 6", Ivs. Mannii. Nov. ; curious, 

 tubicina, 3", Aug. ; rare. 



DORYANTHES. 



Greenhouse plants (ord. Amaryllidea;), of noble 

 appearance. They are increased by suckers, which 

 are given ol? freely by the old plants. Loam and 

 leaf soil in equal proportions, with sand, make a 

 suitable compost. From the great height of the 

 flower stems they can only be grown in roomy 

 homes, 



Principal Species : 



excelsa, S' to Ui'.sum.. sc. 

 Guilt'ovlei, Hi'. sum.,crim. 



Palmcri, 8' to 16', sum., 

 red. 



DORYCNIUM. 



Hardy herbs or sub-shrubs (nrd. LeguminosEc), 

 raised i'rom seeds sown in spring, preferably in 

 gentle heat. Any good garden soil. Dorycniinns 

 .are capital subjects for dry, rather poverty-stricken 

 places. 



Principal Species : 



sull'niticosum, 2' to 3', Je., wh. (*//. Lotus Doryc- 

 niiiin of Liniiions). 



Other Species : 



hcrhaccimi, 1'.', Jy., wh. latifolium, l'to2',Je,, wh. 

 liirsiitum, 1' to'2', Jy., wh. rectum, '2', Je., ro. (*.'/" 



or pk. ; hairy. Lotin rectus). 



DORYOPTERIS (see PTERIS). 



DOSSINIA. 



A genus (ard. Orchidacete), closa to Ancectochi- 

 lus, but differing in the shape of the column. 

 Mannorata is usually met with under the name, of 

 Aniuetoc.hilus Lowii (fnjn. Cheirostylis marmorata), 

 and answers to the same treatment as the other 

 Ancactochllaees. 



DOUBLE FLOWERS. 



Doubling in flowers may arise in a variety of 

 wavs. Frequently the petals art; multiplied at the 

 expense of the stamens and pistil, as in the case of 

 the Camellia and the Stock. At other times 

 multiplication of petals may be produced through 

 a breaking up of the originals. The true double 

 flower being thus deprived of the organs of re- 

 production is unable to set seed ; but as compensa- 

 tion for this it remains in beauty for a longer time 

 than the "single" would have done. This fact, in 

 addition to its increased showiness. has caused 

 double flowers to be much sought after and 

 admired. 



The causes which induce " doubling" are various, 

 and rather subtle. In the case of Stocks, a starving 

 process seems to be the contributing cause. Ker- 

 ria japonica, on the other hand, exhibits a tendency 

 to become double under cultivation, so that lack 

 and excess of nutrition have both to be reckoned 

 with. IVi-haps the most frequent cause is the 



llnri/ii/iliiini (/ Ciiliirinln Ili-etle). 

 Dare t'lvn-t-r (*<; J'cri.itrria). 



stimulus of high cultivation, and il may be noticed 

 in the cases of Begonias, Carnations, Balsams, and 

 other popular races of garden flowers, that any 

 deterioration in the quality of the cultivation tends 

 to reduce the completeness of the doubling. Thus, 

 in the case of double Begonias that are required to 

 set seed, a starving process for a few weeks is 

 necessary. 



Careful selection year after year plays an import- 

 ant part in the fixing of the double strain, ami even 

 then there is always a percentage of reversions to 

 the original singles ; witness the garden Stock. 



The great family of Composites contribute a 

 special section of so-called "double" flowers. 

 Thus single and double Pyrethrums and Chrysan- 

 themums are spoken of, but in these instances, and 

 in many more that might be named, what passes 

 muster as a "petal" is really a flower, and the 

 doubleness or otherwise of the bloom depends upon 

 the number of " flowers " packed into one " head." 

 The long (female) " ray " florets are commonly 

 multiplied at the expense of the shorter (male) 

 florets of the disc. In the Anemone-flowered 

 section we have a great number of disc florets, 

 forming a central cushion, and two or three rows 

 of guard ray (ligulate) florets. 



DOUGLASIA. 



Pretty, rare little plants for the rock garden 

 (tirtl. Primulacese), and resembling the Androsaces. 

 They like a compost of peat, loam, and grit, and 

 require a covering of glass to protect them from 

 damp in winter. Propagation, by seeds or division 

 in spring. Vitaliana is referred to in Androsace, 

 by which name it is generally known in garden-. 



Principal Species : 



Irvigata. 1", spr., aut., 



m., pk. 

 uivalis, 3", Je., pur. 



vitaliana (.V//HS. Amlrosace 

 vitaliaua and Arctia 

 vitaliaua). 



DOWNINGIA. 



Beautiful hardy animals (urd. Campanulacese), 

 with charmingly coloured flowers, suitable for 

 borders or for pots, and raised from seeds sown i'\ 

 a frame in March or in the open in Hay. 



Principal Species : 

 elegaus, 6", Jy., hi., wh. wh., yel. Suitable for 



(XIIH. Clinton'ia elegans). hanging baskets (//. 



rmlchclla, <>", Jy., bl., Clintonia pulchella). 



DRABA. (\VIIITLOW GBASS.) 



Most attractive little rock plants (ord. Cruci- 

 ferje), which produce a charming effect in sunny 

 positions in spring. They generally form dwarf 

 tufts of foliage covered with bloom, rnfortunately 

 the confusion which exists in their nomenclature 

 in gardens is almost hopeless, and it is well-nigh im- 

 possible to procure more than a few species cor- 

 rectly named from nurseries. Propagation is by 

 seeds sown in a frame or greenhouse in spring, or 

 by careful division of the perennials. The former 

 is preferable.. Gritty soil, with sandy peat, suits. 

 The s|>ecies all require a sunny position, and 

 many look extremely well jammed in between 

 the crevices of the rock garden. 



Principal Species : 

 aixoiiles. 3", Mch., yel. ; pyrcnaica, 2A", My., wh., 



a pretty little plant pur. The ' K...-k 



Ai/oon. 3". Ap., yel. (si/ii. Hraiity." a charming 



lasiocarpaV plant, also known a 



Mawii, 2", spr., wh. : a Petrocalli* pyfenalca. 



charming little *]>rci.-. 



