480 



DICHORISANDRA 



DICTAMNUS 



3-4 in. wide, with a short, sharp, rather abrupt point: 

 stem unbranched, robust, spotted : raceme short, densely 

 thyrsoid: sepals white or greenish. Gt. 1808:593. F.S. 

 16:1711. Its chief beauty is the mosaic appearance of 

 the foliage, due to numberless short, transverse, whitish 

 lines, which do not pass by the longitudinal veins of the 

 leaf. The under side of the Ivs. is a rich purplish color. 

 Var. gigantea, Hort., is cult, abroad. 



Var. undata (D. \mdata, C. Koch & Linden). Foliage 

 without any mosaic appearance, the variegation being 

 entirely longitudinal. Each parallel vein lies in the mid- 

 dle of a long, whitish band extending the full length of 

 the leaf. F.S. 17:1763. -Clarke refers D. undata to D. 

 mosaica, but horticulturally they are very distinct. 



Sibertii, Hort. A little known plant with white mid- 

 rib and margins. 



D. acafilis, Cogn. Stemless: Ivs. in a rosette, almost sessile, 

 narrowly oblong, wavy, acutish, short-cuiieate at the base, 

 sparsely pilose on both sides: panicles terminal, sessile, much 

 shorter than the Ivs. Braz. I.H. 41:19. Handsomely varie- 

 gated with countless short, longitudinal lines. D. angustifblia, 

 Lind. & Rod. Stem purple, spotted green: Ivs. oblong-lanceo- 

 late, sessile, glabrous, roundish at the base, acute, about 6 in. 

 long, 2 in. wide at the middle, purple below, marked above with 

 short, transverse, white lines. Equador. I.H. 39:158. D. leu- 

 cophthalmos,'H.ook., differs from all here described in having 

 radical inflorescence, its fls. lying flat on the ground. Lvs. el- 

 liptic, acuminate, green on both sides: fls. blue, with a white 

 eye; stamens 6. Braz. B.M. 4733. D. oxypetala, Hook., is in- 

 stantly recognized by its acute petals, which are purple. Lvs. 

 green on both sides. Braz. B.M. 2721. D. picta, Lodd., has 

 narrower petals than usual, with a white spot at the base, but 

 is told from all others here described by the irregular blotches 

 of purple on the upper side of the Ivs. The purple is the same 

 color as that on the under surface. Braz.? B.M. 4760. L.B.C. 

 17:1667. D. Saundersi, Hook., differs from all others here de- 

 scribed in the extreme density of its head-like inflorescence. 

 Lvs. green on both sides, lanceolate: sepals white, tinged blue. 

 Braz. B.M. 6165. ^r ]yj 



DIGHEOA (Greek, dis, two, and chros, color). In- 

 cludes Adamia. Saxifragacece. This genus contains a 

 rare greenhouse shrub in habit resembling a Hy- 

 drangea, with violet-blue fls. in a pyramidal panicle a 

 foot across, and handsome blue berries, instead of the 

 capsular fruit of Hydrangea. Lvs. persistent, alternate, 

 stalked, widest at middle, tapering both ways, serrate: 

 panicles terminal, many-fld.: fls. blue, lilac, or violet; 

 petals 5 or 6, valvate ; styles 3-5, club-shaped. The 

 genus has only 2 species, the commoner and more vari- 

 able one, D. febrifuga, which is glabrous, being found 

 in the Himalayas, Malaya, and China, while D.pubescens 

 is native to Malaya only. 



febrifuga, Lour. (Adamia versicolor, Hort.). Later 

 writers also include Adamia cyanea, Wall., which 

 Lindley distinguished by its smaller Ivs. and fls., 5 

 petals, and 10 stamens, while* A. versicolor had 7, or 

 sometimes 6 petals, and 20 stamens. Plants are still 

 cultivated abroad under the name of A. cyanea, but it 

 cannot be stated here how distinct they are for horti- 

 cultural purposes. A. versicolor, P.M. 16:322. A. cy- 

 anea, B.M. 3046. iff M. 



DICKSONIA (named for James Dickson, an English 

 botanist, 1738-1822). Cyallieacece. Tree ferns with a 

 distinctly 2-valved inferior indusium, the outer valve 

 formed by the apex of the leaf segment. A small genus, 

 mostly of the southern hemisphere. For D. pilosius- 

 cula, punctilobula and Smithii, see Dennstcedtia. 



Dicksonias are amongst the most important tree ferns, 

 both for their beauty arid because of their relative hardi- 

 ness. In their native countries some of them are occa- 

 sionally weighted with snow, and D. antarctica has to 

 endure frosts. They can be grown in coolhouses, and 

 should be tried southward outdoors in sheltered places. 

 Their trunks are more fibrous than those of most tree 

 ferns, and hence more retentive of moisture, so that 

 they need less care. A good trunk produces 30-40 fronds 

 a year, and retains them until the next set is matured, 

 unless the trees suffer for moisture in winter. Although 

 they rest in winter, the fronds soon shrivel up if the 

 trunks are allowed to get too dry. Dicksonias should 

 have their trunks thoroughly watered twice a day dur- 

 ing the growing season. These waterings should be 



gradually decreased until winter, when the trunks 

 should be kept inerely moist all the time. Only in the 

 hottest summer days is slight shade needed. It is a 

 pity to grow tree ferns in pots, but if this must be done 

 several principles should be observed. The lapse of a 

 single day's watering will often cause serious damage. 

 As a rule, the pots should be of the smallest size con- 

 sistent with the size of the trunk. Three or four inches 

 of soil all round the trunks is enough. The above points 

 are taken from Schneider's Book of Choice Ferns, as 

 tree ferns are little grown in America. 



antarctica, Labill. Scales of the short leaf-stems 

 dense, dark purplish brown : Ivs. 5-6 ft. long, the central 

 pinnae 12-18 in. long ; segments oblong, the sterile in- 

 cised. Australia and Tasmania. G.C. III. 9:81. Trunk 

 sometimes 30-35 ft. high. A very useful decorative 

 plant. 



squarrdsa, Swz. Scales of the short leaf -stem fibril- 

 lose, light colored: Ivs. 3-4 ft. long, the pinnae 9-15 in. 

 long; segments lanceolate, the sterile toothed, the ribs 

 scabrous. New Zealand and Chatham Island. 



L. M. UNDERWOOD and W. M. 



DICLYTKA. This ancient typographical error for 

 Dielytra seems to be immortal. See Dicentra. 



DICTAMNUS (old Greek name, supposed to indicate 

 foliage like the ash : hence Fraxinella, diminutive of the 

 Latin Fraxinus, an ash). Itutacece. GAS PLANT. BURN- 

 ING BUSH. FRAXINELLA. DITTANY. This genus includes 

 an old garden favorite which has a strong smell of 

 lemon, and will sometimes give a flash of light on sultry 

 summer evenings when a lighted match is held near 

 the flowers. It is also one of the most permanent and 

 beautiful features of the hardy herbaceous border. In- 

 stances are known in which it has outlived father, son 

 and grandson in the same spot. The genus has only 

 2 species, and is distinguished from allied genera (none 

 of which have garden value) by the 5 unequal petals, 



707. The Gas Plant Dictamnus albus. 



10 declined stamens, and short stipe, on which the ovary 

 is raised. 



The Gas Plant makes a sturdy, bold, upright growth, 

 and a clump 3 feet high and as much in thickness makes 

 a brave sight when in flower. A strong, rather heavy 

 soil, moderately rich, is best for these plants. They are 

 not fastidious as to situation, succeeding as well in par- 

 tial shade as when fully exposed to the sun, and drought 

 will not effect them w T hen once fairly established. Old, 

 strong clumps are good subjects as isolated specimens 

 on a lawn, and a large patch, planted in the border, is not 

 only effective while in full flower, but the dark, persis- 

 tent foliage is ornamental throughout the season. It is 

 not advisable to disturb the plants very often, as they 

 improve with age, producing taller flower-stems and 

 more of them as they grow older. They are excellent for 

 cutting, especially the white variety. Prop, with diffi- 

 culty by division, but easily by seeds, which are sown in 

 the open ground in fall as soon as ripe, and covered an 

 inch or so. They will germinate the next spring, and, 

 when two years old, the seedlings may be removed to 

 their permanent positions, where they will flower the fol- 

 lowing year. 



