401 



EIjc Crcas'ttrp of USotanij. 



inch or more in length. Three species are 

 known. [A. A. B.] 



DICHLAMYDEOTJS. Having both calyx 

 and corolla. 



DICHOGAMOUS. When the florets of an 

 inflorescence are of two separate sexes. 



DICHOXDRA. A genus of Convolvulacece 



containing two species, one a native of the 



tropical and sub-tropical regions both of 



the Old and the New Worlds, the other 



i found in tropical America. They are pros- 



| trate herbs with small flowers. The calyx 



' five-parted ; the corolla campanulate and 



deeply five-lobed ; the ovary consisting of 



two distinct carpels with one ovule in 



; each of the two cells. The two styles 



| are distinct from the base, with thickened 



i stigmas. [W. C] 



I DICHORISAXDRA. A genus of Comme- 

 \ lynacea? with the habit of Tradescantia, but 



with the filaments neither hairy nor dila- 

 ! ted at the apex. They are Brazilian herbs, 



with lanceolate acuminate leaves, and race- 

 j mose flowers, either terminal or produced 

 ! from the base of the stem. [J. T. SJ 



I DICHOSEMA. There is a group of small 

 , leguminous West Australian bushes in 

 : which the stamens are ten in number and 

 I quite free, and the pods have their mar- 

 i gins rolled inwards, so that they are imper- 

 ; fectly or altogether two-celled, and a cross ' 

 section of them would be somewhat like 

 the figure 8. Tq that group Bichosema be- 

 longs. It differs from the others in having 

 | a very broad vexillum which is bilobed at 

 the apex, and much longer than the wings, 

 these in their turn being a little longer 

 than the keeL There are about half a 

 dozen species, all of them little spiny 

 bushes seldom more than two feet high. 

 The slender stems are clad with minute 

 linear or oblong leaves generally arranged 

 in parcels of three, and accompanied by 

 i slender spines which often exceed them 

 : in length. The flowers are small, yellow, 

 I or purple, solitary in the .leaf-axils or ar- 1 

 ■ ranged in short racemes. [A. A. B.] I 



I DICHOTOMIA (adj. DICHOTOMOUS). 

 Having the divisions always in pairs ; a 

 term equally applied to branches, or veins, 

 or forks. 



DICHROCEPHALA. A genus of Asiatic, ! 

 African, and Australian Composites, which 

 differs from its near allies chiefly in the 

 convex receptacle of the flower-heads. They 

 are branching herbs, with oval coarsely 

 toothed or lyrate sometimes pinnatifid 

 leaves ; the branches being terminated by 

 panicles of nearly globular flower-heads, 

 about the size of a small pea. Theachenes 

 are compressed, those of the outer florets 

 without pappus, and those of the inner 

 series with a pappus of one or two short '■ 

 hairs. Of the five species known, all are 

 common weeds in the countries where they 

 grow, and of no beauty. [A. A. B.] 



DICHYNCHOSIA. A genus of Cuno- ! 

 niacem from Celebes. A tree with oppo- 

 site pinnate leaves, the few leaflets of i 



which are oblong ovate, coarsely serrated, 

 with the under surface (as well as the 

 branchlets and inflorescence) covered with 

 stellate down. The stipules are large and 

 kidney-shaped. The flowers grow in 

 axillary panicles.which are much branched 

 in a corymbose manner ; the calyx five or 

 six-parted, persistent ; stigmas two, diverg- 

 ing; capsule two-beaked ; seeds numerous, 

 with a membranous wing. [J. T. S.J 



DICKIEA. A curious genus of Biatoma- 

 cece, in which the frond assumes an ul- 

 void form, as it does a filiform in Moiiema 

 and Schieonema and a globose in Berkeleia. 

 When the gelatinous element in these 

 genera is removed, the frustules are found 

 to be of precisely the same nature as those 

 in genera where the gelatinous element is 

 extremely reduced, or where it only tends 

 to keep a quantity of frustules together in 

 an irregular stratum. [M. J. BJ 



DICKSONTA. A genus of noble mostly 

 arborescent ferns of the polypodiaceous 

 group, and typical of the section Bick- 

 soniem. Their stems are often thick and 

 trunk-like, but sometimes decumbent and 

 criniferous. The fronds are large, generally 

 decompound, and leathery, forming a 

 noble tuf t or crown ; and the sori are globose 

 or shortly oblong, transverse, and marginal , 

 with a coriaceous indusium of two valves, 

 of which the outer, formed of a lobule of 

 the frond, is cucullate, and the inner usu- 

 ally smaller and less convex ; the veins 

 are free. 1). antarctica is a very beautiful 

 tree fern often seen in green-houses, having 

 been freely imported from our Australasian 

 colonies. Others occur in St. Helena, 

 Brazil, Juan Fernandez, Columbia and 

 Java. One pinnate species, D. abm.pt a, 

 which is only found in Bourbon, has quite 

 the aspect of a Nephrolepis. The sori are al- 

 ways more or less recurved from the plane 

 of the frond. [T. M.] 



DICLESIUM. A one-seeded indehiscent 

 fruit enclosed within a hardened perianth, 

 as in the marvel of Peru. 



DICLIDANTHERA. A genus of dicoty- 

 ledons, founded on two Brazilian shrubs 

 which are in many respects allied to Sapo- 

 tacece. Differing, however, as it does in a 

 slight irregularity in the flowers, in the 

 curious two-valved anthers, and in some 

 measure in the structure of the ovary, the 

 genus has been removed from that family, 

 and eminent botanists have severally pro- 

 posed associating it with Polygalacece., Ha- 

 mamelidacece, or even Byttneriacem. 



DICLIDIUM. A genus of plants belong- 

 ing to the Cyperacer.e. Only one species is 

 described, namely, B. ferox, a native of 

 South America. [D. MJ 



DICLIDOCARPUS. The name given to 

 a genus of Tiliacece, remarkable for the 

 form of its fruit, which is a somewhat 

 woody compressed two-celled capsule, 

 with numerous seeds. It is about an inch 

 long, rather more in breadth, and nearly 

 inversely heart-shaped in form. When 

 ripe it splits into two portions, and has 



