H E A 



283 



HE A 



ing air, without inconvenience, which 

 rendered the silver-mountings of my 

 green spectacles too hot to be borne 

 without their occasional removal. 



So do certain plants flourish in hot- 

 water springs of which the temperature 

 varies between the scalding heats of 

 from loO*-' to ISO^ of Fahrenheit's ther- 

 mometer; and others have been found 

 growing freely on the edges of volca- 

 noes, in an atmosphere heated above 

 the boiling point of water. Indeed, it 

 is quite certain that most plants will 

 better bear, for a short time, an elevat- 

 ed temperature which, if long continu- 

 ed, would destroy them, than they can 

 a low temperature. Thus a temperature 

 much above the freezing point of wa- 

 ter, to orchidaceous and other tropical 

 plants, is generally fatal if endured by 

 them for only a few minutes ; whereas 

 a considerable elevation above a salu- 

 tary temperature is rarely injurious to 

 plants. But this is not universally the 

 case ; for the elegant Primula marginata 

 is so impatient of heat that, although 

 just about to bloom, it never opens a 

 bud, if brought into a room in which 

 there is a fire. 



The temperature should always be 

 regulated, in our hot-houses, with a 

 due regard to the light. At night it 

 should be so low as to put the circula- 

 tion of the sap into a comparative state 

 of rest; and in dull days the tempera- 

 ture should be full 10^ lower than in 

 those of bright sunshine. 



HEATHS {Erica). This truly beau- 

 tiful tribe is in the climate of the United 

 States of but little interest. Scarcely 

 half a dozen of the almost countless 

 species and varieties of Erica have 

 proved capable of resisting the effects 

 of our restless climate. It is a curious 

 fact, that, though this genus is diffused 

 over Europe, Asia, and Africa, not a 

 single species has been found in the 

 Western hemisphere. 



Varieties. — Of these the following are 

 good selections : — 



HARDY CAPE HEATHS, FOR FLOWERING 

 DURING THE SUMMER MONTHS. 



Erica Bowieana, white. 



Grandiflora, yellow. 



Ventricosa, pink. 



Echitlora, purple. 



Beaumontiana, blush. 



Mundula, pink. 



Cerinthoides, scarlet. 



Erica Ampullacea. 



Aristata,dark crimson and pink. 



Aggregata, purple. 



Vindiflora, green and pink. 



Phrysodes, whiXe. 



USEFUL KINDS ARE : 



Hartnelli, pink. 



Aristata ]\Iajor, red. 



Acuminata longitlora, purple. 



Tenuiflora, white, with pink 



shade. 



Inflata, white. 



Archeriana, scarlet. 



Depressa, yellow. 



Elegans, light purple. 



Cavendishii, yellow. 



Mutabilis, light purple. 



Retorta Major, pink. 



Lamberti Rosea, flesh-coloured. 



Hyemalis, purple, lipped with 



white. 



Tricolor, red. 



Lirinaioides Superba, purple, 



with white tip. 



Jasmini, flora alba, white, and 



all the varieties of Ventri- 

 cosa. 



VARIETIES BLOOMING BETWEEN NOVEM- 

 BER AND MAY. 



Erica Verticillata. 



Mammosa, M. pallida. 



Hyemalis. 



Willmoreana. 



VVestcottii. 



Grandinosa. 



Arbuscula. 



Umbellata. 



Rubra P., alba. 



Pyramidalis. 



Transparens. 



^— Regermirans. 



Mr. Reid very justly remarks, "that, 

 in small establishments, the green-house 

 being generally furnished with vines, to 

 keep plants in them in summer is out of 

 the question ; he therefore selects three 

 or four plants of only the winter flower- 

 ing sorts, such as would keep up a show 

 of bloom from November till April. 

 Early in May the plants might be all 

 taken out, and the house should be shut 

 up for the purpose of forwarding the 

 vines." 



With something like the following 

 selection, a very nice show of bloom 

 might be kept up during all the time 

 that it is necessary to have the plants 

 in the house ; and thev are, with very 



