RHINOCEROS HORNRILL. 



RHODODENDRON. 



04 



Although the number of extinct specie* equal* those which are 

 now tiiirtiny, no remains of thu genus have aver been found in 

 America or Australia. This peculiar form of pachydermatous creatures 

 appear* to lure been confined from iU first creation to the samo great 

 natural division of Uie world's surface to which the existing repre- 

 MnUtirM of that form are still peculiar. 



KHINoCKUOS HOKNBILU [HonsBlLLB.] 



RlllXuLOPHrXA. [CBKIBOITIBA.] 



IMIINdLOI'HL'S. [CaEIHOPTHU.] 



KIU'XOPHIS (Wagler),agonu* of SerpenU. 



RHINOPI'KUS. [EBFETOX.I 



KHINorOMA. [CHEIROPTERA.] 



RHIPIUU'RA. [McscicAriD*.] 



RHIPIPTERA, a name giren by Latreille to the order previous]; 

 named by Mr. Kirby Slrtpriptera. This order embraces the genera 

 Xntoi, Sttfopi, Elencktu, and others. [STRKI-SIITERA.] 



RHIS8OPTBRA, [RBIPIPTERA.] 



UHIZAXTHK.K, RAixmtlu, Rhi:oyent, a small class of PlanU, com- 

 prising the orders Balaaopkaracetr, Cytinaeea, and Itajfletiacca. They 

 are parasitical plant*, destitute of true leaves, in the place of which 

 they are furnished with cellular scales. Their stem is either an amor- 

 phous fungous mass or a ramified mycelium, and is very imperfectly 

 upplied with spiral vessel*, which are sometimes wholly deficient. 

 They are of a brown yellow or purple colour, never green. They 

 produce flowers which have genuine stamens and carpels, and are 

 surrounded by a whorl of petaloid bodies. " They possess ovules, but 

 their aeed is not known. 



These plant* have been regarded by Lindley, Endlicher, and other 

 botanist*, as sufficiently distinct to warrant their being placed in a 

 class by themselves. Their flowers, stamens, and ovules, indicate their 

 relation to the phanerogamic plants, whilst their mycelial stem, para- 

 sitic habits, and cellular structure ally them with the fungi and other 

 low forms of vegetation. Mr. Brown however is of opinion that the 

 Rbizanths are but less developed forms of Exogenous Plants. He 

 regard* them as having affinities with Arutolochiacea, and other 

 order* of Exogens. More recently Mr. Griffiths bos adopted the 

 views of Brown, and advanced a number of arguments in favour of 

 their being degraded forms of higher plants, and not a permanently 

 low form of vegetation. He thinks the relations of Rhizanths various. 

 Thus he places Myttropetalon near Prottacea; and Santalacete; Sarco- 

 plylc and Balanophora he places near Urticacea. Finally, he places 

 Tkumia between Taecacea and Burmanaiacete. 



The fallowing are the orders of Mizanthete as recognised by 

 Lindley: 



Ovule* solitary, pendulous ; fruit one-seeded . . Batanophoraccie. 

 Ovules 00, parietal; fruit many-seeded; calyx 



3-4-6-parted ; anthers opening by slits . 

 Ovule* 00, parietal ; fruit many-seeded ; calyx 1 

 5 parted ; anther, opening by pores . . . } 

 ICHIZOBOLAC'E.E, Rkuoboli, a natural order of Plants, consisting 

 of tree* of very largo size. The leave* are opposite, digitate, coria- 

 ceous, with a pointed stalk and no stipules ; flowers large, regular, 

 arranged in raceme*, with their stalk* pointed at the base and below 

 the apex ; the *epals are 5 or 6, more or less combined, imbricated 

 in activation ; petal* 5 to 8, equal-sided, but unequal thickish, arising 

 along with the stamens from a nypogynous diec ; fruit of several com- 

 bined indcbiftoent one-seeded nut*; seed rcniform, exalbuminous, 

 with a cord dilated into a spongy excrescence; radicle very large. The 

 specie* are found in South America. They are large timber-trees, 

 some of which yield edible fruit. It is from trees of thu order that 

 are produced the Souari (or Suwarrow) Nut* of the shops, the kernel 

 of which i* one of the most delicious fruit* of the nut kind that in 

 known. An oil is extracted from them not inferior to that of the 

 olive. The timber of the tree i* used for ship-building. (Liiidloy, 

 Vtgetablt Kingdom.) 



x ! . 

 . / <** 



HHI'XODUa [Pun.] 



RH1/.OMOKPHA, a genus of PlanU belonging to the natural order 

 nf l-'unyi, having altogether the appearance of the root of a tree. The 

 specie* are found in damp cellar*, old wall*, mines, and other subter- 

 ranean place*, where they sometimes acquire a phosphorescent state, 

 which renders them exceedingly curious object*. Nothing is at 

 pment known of tlieir mode of reproduction or origin ; but it in 

 thought that they spring out of decaying wood buried in the ground. 

 The genn* RhiMmorpha i* not included in Hooker'* ' Englinh Flora,' 

 but it U mentioned by Mr. Berkley, who wrote the raycological depart- 

 ment of that work, a* a fungou* production, originating in tan-pits. 

 Several specie* are mentioned by author*, of which R. meduUaria it 

 the most common. This U so like the root of a tree divided into 

 numerous fibres, that it i* probably often mistaken for it Indepen- 

 dently however of it* cellular organisation, so different from that of 

 woo'l, it may always be known by its musty smell. 



IMlI/.ol'lliiKA. [HmzoriiOHACM.] 



BHIZOPHORACE.fi, Mcatyrorf*, a natural order of Exogenous 

 Plant*, native* of the shore* of the tropics, where they root in the 

 mud, and form a close thicket down to the verge of the ocean. 

 They are tree*, or shrubs, with simple opposite leaves, having decidu- 



ous interpetiolary stipule*. The calyx i* adherent, with 4-12 valvate 

 lobe*; petal* 4-12; stamens twice or thrice as many ; ovary 2-4-celled, 

 with two pendulous ovules in each cell. The fruit is monospermal, 

 indehiacent, crowned by the calyx. Seed exalbuminous, embryo 

 germinating in the pericarp. There are 21 species and 5 genera. The 

 bark of the trees is usually astringent, and U employed in tanning 

 and as a febrifuge. The wood of several is described a* being hard 

 and durable. The following species of Kfiizopliora are the beat known 

 forms of the order : 



A'. Mangle, the Common or Black Mangrove, is found abundant 

 on the shores of the ocean, and within the delta of the Ganges, 

 where it grows to a considerable size. The seed of this specie*, 

 which is from one to two feet long, very quickly gives rise to a young 

 tree, and, as mentioned by Browne in his ' History of Jamaica,' if 

 the apex from whence the root issues be stuck only a little way in 

 the mud, the leaves quickly unfold at the opposite end. The wood 

 is dark-red, hard, and durable, and the bark is used for tanning 

 leather. 



R. Candel, Red Mangrove, or Paletuvier. The branches of this 

 species, though they bend downwards, do not take root in the ground. 

 The wood is heavy, of a deep-red, and takes a fine polish. The bark 

 is used in dyeing red, is astringent, and used in the West Indie* for 

 the cure of fevers, a/well as of the bites of venomous insects. 



S, gymnorhiza grows to a considerable size where the spring-tides 

 rise over it, as in the delta of the Ganges. The wood is yellow, hard, 

 and durable ; has a sulphurous smell, and burns with a vivid light ; 

 is chiefly used by the natives for fire-wood and for making post* for 

 constructing their houses. The pith of the wood, boiled in palm wine 

 or with fish, is used as food. 



RHIZOPHY'SA. [AcALEPHAl 



RHIZO'STOMA. [ACALEI-H.K.] 



RHIZOSTO'MID^E. [ACALEPH.E.] 



RHIZOTROGUS. [MELOLONTIIID^.] 



RHODALITE, a Mineral which appears to consist of small rect- 

 angular prisms with square bases. Hardness about 2. Colour between 

 rose-red and flesh-red. Specific gravity 2. Before the blow-pipe per 

 se not altered. With carbonate of soda fuses into a greenish-blue 

 transparent bead in the exterior flame, becoming yellow in the interior 

 flame : with borax gives a transparent colourless bead ; with phos- 

 phate of soda does not fuse. It is found in Ireland, occurring probably 

 in an amygdaloidal rock. An analysis by Mr. Richardson gives 



Silica 65-9 



Alumina 8*3 



Peroxide of Iron, and trace of Oxide of Man- 1 , . . . 



ganese J 



Lime 11 



Magnesia 0*6 



Water ... .... 22-0 



99 '3 



RHODEA. [COAL PLANTS.] 



RHODIOLA. [SEDCM.] 



RHODIUM. [PLATINUM.] 



RHODIZITE, a Mineral resembling Boraclte [Bonon] in its crystal*, 

 but it tinges the blow-pipe flame deep red. It occurs with the lied 

 Tourmaline of Siberia. (Dana.] 



HHODOCRINI'TES. [ExciusiTEs.] 



RHODODENDRON, a gouus of Plants belonging to the natural 

 order Ericactce. The species are evergreen ihrubs, very commonly 

 cultivated in our gardens and shrubberies, and differing from Azalea 

 principally in the stamens, being 10 instead of 5, in the corolla being 

 campunulale, not tubular, and in the foliage being hard and evergreen. 

 The specie* arc nearly related to each other, and occur both in the 

 New and Old Worlds. 



R. J'unticum is the species to which most of the varieties of our 

 gardens belong. The leaves are oblong-lanceolate, glabrous on both 

 surfaces, attenuated towards the thick petioles, with a streak on the 

 upper surface and of a wide lanceolate form, racemes short and corym- 

 bose. It is a native of Asia Minor in Pontus, and of Gibraltar, Spain, 

 nnd the Caucasus, in wet places, in beech and alder coppices. The corolla 

 i* Urge, purplish, with ovate, acute, or lanceolate segments. The calyx 

 minute, 5-toothcd, somewhat cartilaginous. At one time it was sup- 

 posed that it was this plant which rendered the honey of Asia Minor 

 poisonous, but it ha* been ascertained that the effect U really produced 

 jy Aialta I'onlica. 



R.arboreum,frae Rhododendron, has lanceolate leaves, acute, silvery 

 xmeath, tapering to the base ; peduncles and calyxes woolly ; segment* 

 of corolla 2-lobed, with crenulating curled tnarginx, capsule 10-celled, 

 amentose. It is a native of the warmer part* of India, and is one of 

 .he most beautiful of all trees, but too delicate to bear the open air 

 'n England. 



R. chryianthum has acute leave* attenuated at the base, oblong, 

 ;labroun, reticulately veined, and of a rusty colour beneath ; flowers 

 ind buds clothed with rusty tomentum ; pedicels hairy ; calyx hardly 

 any ; segment* of the corolla rounded ; ovarium tomentose. It is a 

 lativo of Siberia on the highest mountains, and of the Caucasus. The 

 ilant and it* effect* were first described by Gmelin and Steller, who 

 mention it as used in Siberia for the cure of rheumatism ; with us it i* 

 used in decoction as a substitute for calchicum. 



