THENARDIA 



854 



THIBAUDIA 



THENA'RDIA. (Named after M. Thenard, a French 

 chemist. Nat. ord. Dogbanes [Apocynaceae]. Linn. 

 5-Pentandria, i-Monogynia.) 



Stove evergreen climber. Cuttings of stubby side- 

 shoots in sand, under a bell-glass, and in heat ; sandy, 

 fibrous loam and peat, with a little charcoal. Winter 

 temp., 55 to 60 ; summer, 65 to 85. 

 T. floribu'nda (bundled-flowered). 10. Blue. Mexico. 



1823. 



THEOBRO'MA. Chocolate- tree. (From theos, a god, 

 and broma, food ; poetically, food for the gods. Nat. 

 ord. Sterculiads [Sterculiacea?]. Linn. i&-Polyadelphia, 

 i-Decandria.) 



The seed of T. Caca'o is the chief ingredient in chocolate 

 and cocoa. Stove evergreen trees. Cuttings of half- 

 ripened shoots in sand, under a bell-glass, in heat ; 

 fibrous loam and sandy peat. Winter temp., 55 to 65 ; 

 summer, 65 to 88. 



T. angustifo'lia (narrow- leaved). See T. SPECIOSA. 

 bi'color (two-coloured). 16. Brown. New Grenada. 



1820. 

 Caca'o (cacao). 16. Brown. Trop. Amer. 1739. 



" Cocoa." 



caribce'a (Caribbean). Yellow. W. Ind. 1821. 

 Guazu'ma (Guazuma). See GUAZUMA ULMIFOLIA. 

 guiane'nsis (Guiana). See T. CACAO. 

 specio'sa (showy). Brazil. 



THEODO'REA. (A commemorative name. Nat. ord. 

 Orchidaceae.) 



Stove epiphytal orchid. Offsets. Sphagnum, fibre of 

 peat, and crocks. 



T. gomezoi'des (Gomezia-like). \. White, with orange- 

 buff blotch. Brazil. 1903. 



THEOPHRA'STA. (Named after Theophrastus, the 

 father of natural history. Nat. ord. Ardisiads [Myrsin- 

 aceae]. Linn. 5-Pentandria, i-Monogynia.) 



Stove evergreens. Cuttings of ripe young shoots in 

 sand, under a bell-glass, in heat ; sandy loam and 

 fibrous peat. Winter temp., 50 to 58 ; summer, 60 

 to 85. 

 T. argyra'a (silvery). 1860. 



imperia'lis (imperial). W. Ind. 1864. 



/ssiw'j(Jussieu's). 3. White. St. Domingo. 1818. 



,, latifo'lia (broad-leaved). See CLAVIJA LATIFOLIA. 



longifo'lia (long-lead). See CLAVIJA ORNATA. 



macrophy'lla (large-leaved) . See CLAVIJA MACRO- 



PHYLLA. 



pinna' ta (pinnate). See TALISIA PRINCEPS. 



smara'gdina (emerald green). See DEHERAIMA 



SMARAGDINA. 



untbro'sa (shady). See CLAVIJA UMBROSA. 

 THERE'SIA PE'RSICA. See FRITILLARIA PERSICA. 



THERMOMETER. This instrument is the only un- 

 failing guide for the gardener in regulating the heat to 

 which he allows the roots and foliage of his plants to be 

 subjected. 



Fahrenheit's is used chiefly in Britain, Holland, and 

 North America, the freezing point of water on which is 

 at 32 ; and its boiling point, 212. Reaumur's ther- 

 mometer was that chiefly used in France before the 

 Revolution, and is that now generally used in Spain, and 

 in some other continental states. In its scale the 

 freezing point is o ; and the boiling point, 80. On 

 Celsius or the Centigrade thermometer, now used through- 

 out France, and in the northern kingdoms of Europe, 

 the freezing point is o ; and the boiling point, 100. 

 Hence, to reduce degrees of temperature of the Centi- 

 grade thermometer and of that of Reaumur to degrees of 

 Fahrenheit's scale, and conversely : 



RULE i. Mutiply the Centigrade degrees by 9, and 

 divide the product by 5 ; or multiply the degrees of 

 Reaumur by 9, and divide by 4 ; then add 32 to the 

 quotient in either case, and the sum is the degrees of 

 temperature of Fahrenheit's scale. 



RULE 2. From the number of degrees on Fahrenheit's 

 scale subtract 32 ; multiply the remainder by 5 for 

 Centigrade degrees, or by 4 for those of Reaumur's scale, 

 and the product, in either case, being divided by 9, 

 will give the temperature required according to Fahren- 

 heit's. 



To ascertain the internal temperature of a hothouse, 

 the thermometer should be fixed near its centre, against 



a pillar, and under a cupola, or little roof, shading it 

 from the sun. 



A self-registering thermometer should be in every 

 house, for it shows the highest and lowest degrees of 

 heat which have occurred in the twenty-four hours ; 

 and therefore serves as a check upon those to whose 

 care they are entrusted. 



Bregazzi's bark-bed thermometer is an excellent instru- 

 ment for ascertaining the bottom-heat of hot-beds, bark- 

 pits, &c. It is a thermometer inclosed in a metal tube, 

 perforated to admit the heat, pointed, so as to be easily 

 thrust down, and with a small door in the side, for 

 observing the degree of temperature shown by the scale. 



THERMO'PSIS. (From thermos, a lupine, and opsis, 

 like; lupine-like. Nat. ord. Leguminous Plants [Legumi- 

 nosas]. Linn. lo-Decandria, i-Monogynia. Allied to 

 Piptanthus.) 



Hardy herbaceous yellow-flowered perennials. Chiefly 

 by seeds sown in April ; light, sandy loam. 

 T. barba'ta (bearded), ij. Purple. June. Himalaya. 



1855- 



,, carolinia'na (Carolinian). i\. Yellow. N. Amer. 

 ,, corgone'nsis (Corgon). i. July. Altaia. 1820. 

 faba'cea (bean-like). 2. June. Kamtchatka. 1811. 

 ,, laburnifo'lia (Laburnum-leaved). See PIPTANTHUS 



NEPALENSIS. 



lanceola'ta (spear-head-teawd). i. June. Siberia. 



1779. 



lupinoi'des (Lupine-like). See T. LANCEOLATA. 

 mo' His (soft). i. Blue. June. N. Amer. 1824. 

 monta'na (mountain), i. Yellow. June. N. Amer. 



iSi8. 



nepaule'nsis (Nepaul). See PIPTANTHUS NEPALENSIS. 

 ,, au'rea (golden). See PIPTANTHUS NEPALENSIS 



AUREA. 

 rhombifo' lia (rhombus- leaved). 2. Yellow. June 



N. Amer. 



THEROPO'GON. (From theros, summer, and pogon, a 

 beard ; the plant resembles Ophiopogon. Nat. ord. 

 Liliaceae. Allied to Polygonatum.) 

 T. pa'llidus (pale). |. Pink. Himalaya. 1875. 



THE'SIUM. (An old Greek word, thesion. Nat. ord. 

 Santalaceae.) 



Hardy perennial herb parasitic on the roots of various 

 things. Seeds ; divisions. Should be planted amongst 

 grass or other low plants. 



T. drupa'ceum (berried). See LEPTOMERIA BILLARDIERI. 

 humifu'sum (spread-on-ground). J-. Green. Sum- 

 mer. Europe (Britain). " Bastard Toad-flax." 

 linophy'llum (flax-leaved). See T. HUMIFUSUM. 



THESPE'SIA. (From thespcsios, divine ; one of the 

 trees often planted round places of worship in India. 

 Nat. ord. Mallowivorts [Malvaceae]. Linn. i6-Mona- 

 delphia, 8-Polyandria.) 



Stove evergreen trees. Cuttings of stubby side-shoots 

 in sand, in May, under a bell-glass, in bottom-heat ; 

 fibrous, sandy loam, and a little leaf-mould. Winter 

 temp., 48 to 55 ; summer, 65 to 85. 

 T. grandiflo'ra (large-flowered). 30. Scarlet. Point 



Rico. 1837. 



La'mpas (lamp). See T. MACROPHVLLA. 

 macrophy'lla (large-leaved). 10. Pink. Trop. Asia 



and Africa. 1806. 

 popu'lnea (poplar-leaved). 30. White. Trop. Asia 



and Africa. 1770. 



guadalupe'nsis (Guadeloupe). 30. Guadaloupe. 

 ,, tomento'sa (felted). Mexico. 



THEVE'TIA. (Commemorative of M, Thevet. Nat. 

 ord. Apocynaceae.) 



Evergreen stove shrubs. Cuttings in sand, in a close 

 frame, with bottom-heat. Fibrous loam, peat, and sand. 

 T. Ahou'ai (Ahouai). 15-20. Yellow. June. Brazil. 



1739. 



nereifo'lia (Nerium-leaved). 12. Yellow. June. 

 ova'ta (egg-shaped). 3. Yellow. Mexico. Trop. 



Amer. 1735. 

 Ycco'tli (Yccotli). 5-8. Yellow. June. Mexico. 



1800. 



THIBAU'DIA. (Named after Thiebaut de Berneaud, a 

 French botanist. Nat. ord. Whortleberries [Vacciniaceae]. 

 Linn. S-Octandria, i-Monogynia.) 



