DICTAMNUS 



&\bua,Lum.(D.Fraxinma,Pers.}. Fig. 707. A vig- 

 orous, symmetrical, hardy herb, with glossy, leathery 

 foliage surmounted by long, showy terminal racemes of 

 good-sized, fragrant fls. Lvs. alternate, odd-pinnate; 

 Ifts. ovate, serrulate, dotted with oil glands: fl.s. white. 

 Eu., N.Asia. (in.;i5:701. A. P. 5:328. Gng. 5:321. Var. 

 rdbra, Hort., has rosy purple fls., the veins deeper 

 colored. \'ar. giganMus, Hort. {B. qiganteus, Hort.), 

 was recently introduced. j. b. Keller and. W. M. 



DICTYOGKAMMA (Greek, ne»ed lines). PohjpodiA- 

 cew. A genus of a few Japanese and Pacitic Island 

 ferns, with naked sori, which follow the course of the 

 reticulated veins. The species are sometimes referred 

 to Gymnogramma. Strong-growing indoor fern, useful 

 for specimen plants. 



Jap6nica, Pee. Lvs. simply pinnate or bipinnate at the 

 base, lK-2 ft. high, the pinuEB 6-12 in. long and an inch 

 wide ; sori extending from the midrib to the edge. 

 Japan and Formosa. Also known as Gymnogramma 

 Japonicii. An interesting fern of rather strong growth, 

 and very distinct in appearance. Grows best in a mod- 

 erate temperature — for example, 5.5-60° — and requires 

 an open and well-drained soil of peaty character. 



L. M. Underwood and W. H. Taplin. 



DICTYOSPfiEMA (Greek, Me^cd seed). Palmdcew, 

 tribe Arece(c. Ttjis genus of Areca-like palms contains 

 a few species of considerable commercial importance, 

 the young plants being used chiefly for house and table 

 decoration. Slender spineless palms, with a ringed 

 trunk: lvs. equally pinnatisect; segments linear-lanceo- 

 late, acuminate or bifid, the apical ones confluent; mar- 

 gins thickened, recurved at the base; midrib and nerves 

 prominent, sparsely clothed with persistent scales 

 beneath, or naked; rachis and petiole slender, scaly, 

 3-sided, furrowed, sheath elongated, entire: spadix on a 

 short glabrous or tomentose peduncle, the branches erect 

 or spreading and fiexuose, the lower ones with mem- 

 branaceous bracts at the base: spathes 2, complete, dor- 

 sally compressed, papery, the lower one 2-crested ; 

 flower-bearing areas much depressed: bracts and bract- 

 lets scaly : pistillate fls. rather large, white or yellowish : 

 fr. scaly, small, olive-shaped or subglobose. Species 2 

 or 3. Indian Archipelago. Jaked G. Smith. 



Dictyosperma is a genus of medium-sized palms of 

 slender habit, and having pinnate leaves. At least two 

 species of Dictyosperma {rnbra and alba) have been 

 included among commercial palms for some years p.ast, 

 though not grown in such quantities as the popular 

 Kentias, Arecas and Latauias. D. aurea is also occa- 

 sionally seen in commercial collections. 



The cultivation of these palms does not present any 

 great dilHeulties, similar conditions to those required by 

 Chri/salidocarptis lutescens answering well. These 

 conditions may be briefly summarized as follows: A soil 

 consisting of well rotted sod, to which has been added 

 about one-sixth, in bulk, of good stable manure, firm 

 potting, and an abundance of water both at the root and 

 overhead, a night temperature during the winter of 60 

 to 65° P., and moderate shade on the glass from March 1 

 to November 1. This treatment applies especially to 

 young stock, and may be modified somewhat with old 

 and well established specimens, the latter enduring a 

 slightly lower temperature without injury, providing 

 they are not overwatered. Dictyospermas are rather 

 susceptible to the attacks of some insects, notably red 

 spider and various scale insects, and, if allowed to be- 

 come very dry, are liable to lose their lower leaves, the 

 most satisfactory species being D. rubra. Propagation 

 by seeds, which germinate in 6 to 8 weeks, when sown in 

 a warm greenhouse. ^ jj Taplin. 



alba, Wendl. & Drude {Areca alba, Bory. Ptycho- 

 spirma alba, Schpfif. ). Distinguished by the whitish 

 petioles and the whitish green veins of the lvs. Caudex 

 40-.50 ft. high, 8-9 in. in diam., dilated at the base: lvs. 

 8-ri ft. long; petiole 6-18 in. long, grooved down the 

 face; segments 2^/^-3 ft. long, 2-3 in. wide, 7-nerved; 

 veins and margins green or reddish: branches of the 

 spadix 6-18 in. long, erect or slightly reflexed, zigzag 

 when young. 



31 



DIDYMOSPERMA 



481 



atirea, Wendl. & Drude {Areca aurea, Hort.). Dis- 

 tinguished by the yellow or orange petioles and veins 

 of young plants. Caudex about 30 ft. high, smaller and 

 more slender than the preceding: lvs. 4-8 ft. long; peti- 

 ole 8 in. long; segments l>2-2 ft. long, 1 in. wide; sec- 

 ondary veins .scarcely visible: branches of the spadix 

 rigidly erect, 9-11 in. long. 



furSuricea, Wendl. & Drude (Areca furhtricea, 

 Hort.). Like D. rnbra, but the petiole and leaf -sheath 

 of the young plant tomentose. 



rtbra, Wendl. & Drude (Areca rubra, Hort.). Re- 

 sembling D. alba, but the lvs. of the young plants 

 darker green, the primary veins and margins dark red, 

 the redness disappearing very much in adult plants: 

 branches of the spadix longer and more reflexed. 



Jarkd G. Smith. 



DICYBTA is a gesneraceous genus closely allied to 

 Achimenes, but with smaller fls. and different anthers. 

 It has 2 species, both from Guatemala. i>. Candida is 

 cult, abroad as Achimenes Candida. 



DIDlSCUS. See Trachymene. 



DIDYMOCHL.ffiNA (Greek, twin cloak: alluding to the 

 indusium ) . PolypodiiLceie. A small genus of greenhouse 

 ferns of rather coarse foliage. Indusium elliptical, 

 emarginate at the base, attached along a central vein, 

 free all round the margin. 



lunul&ta, Desv. (D. trunculdta, Hort.). Lvs. clustered 

 from an erect caudex, bipinnate, 3-6 ft. long ; pinnules 

 almost quadrangular %-l in. broad, entire or slightly sin- 

 uate, each bearing 2-6 sori. Cuba to Brazil ; the same 

 or an allied species in Madagascar and Malaya. — /*, ht- 

 nulata is a very attractive fern while in a small state, 

 but its articulated pinnules are a drawback as a com- 

 mercial species, rendering it of little value for house 

 decoration. l. ji. Underwood and W. H. Taplin. 



The following points are condensed from Schneider's 

 admirable work. The Book of Choice Ferns: D. lunulala 

 is one of the most distinct ferns in cultivation. It looks 

 like a tree maidenhair, but the stems, instead of being 

 black and slender, are thick and fleshy and the leaves 

 are fleshier than any Adiantum. In cult, the trunk is 

 only a few inches high, but the fronds are 4-6 ft. long 

 and densely covered with long, brown, chaffy scales. 

 The metallic color of its young fronds is a fine feature. 

 This is a warmhouse fern, and may be used for subtropical 

 bedding. It has a bad trick of droppinc its pinnules if 

 allowed to get too dry at the root, but soon rallies under 

 liberal treatment. 



DIDYMOSPfiRMA (Greek, double-seeded). Palmd.ceo', 

 tribe Ar!cnt. Low or erect palms with slender trunks. 

 Leaves trnninal, unequally pinnatisect, silvery-scaly be- 

 low ; segments opposite, alternate, solitary, or the 

 lower ones in groups, cuneate at the base; obovate-ob- 

 long or oblanceolate, sinuate-lobed and erose, the ter- 

 minal one cuneate; margins recurved at the base; mid- 

 nerve distinct, nerves flabellate; sheath short, fibrous: 

 spadices with a short, thick peduncle and thick branches : 

 spathes numerous, sheathing the spadix: fls. rather 

 large: fr. ovoid or oblong. Species 6. India and Malay 

 Archipelago. 



porphyrocArpon, Wendl. & Drude ( WalUchia por- 

 phyrocdrpa. Mart.). Stems reedy, 3-6 ft.: lvs. 5-8 ft. 

 long ; leaflets 9-15 in. long, distant, narrowly oblong, 

 long cuneate, blunt, or sinuately 2-3-lobed, truncate, den- 

 ticulate, glaucous beneath. Java. 



Didymosperma is a genus of East Indian palms of 

 moderate growth, containing possibly 8 .species, most 

 of which are stemless or else forming but a short trunk, 

 the pinnate leaves rising from a mass of coarse brown- 

 ish fibers that surroimd the base of the plant. The leaf- 

 lets are of irregular shape, bearing some resemblance to 

 those of Caryota, and the plants frequently throw up 

 suckers from the base. The members of this genus are 

 not very common in cultivation. The species that is most 

 frequently seen is the plant known to the trade as 

 £>. caryotoides, an attractive warmhouse palm that has 

 also appeared under the synonym Bariva caryotoides. 



