EPIPHYTES. 



EPIPHYTES. 



686 



part of Orchidaceous Epiphytes, there are some striking exceptions 

 that require to be pointed out, both with regard to atmospheric 

 moisture and to the temperature requisite for their production. 



Mr. Allan Cunningham has shown in the ' Botanical Register,' fol. 

 1699, that in Australia there are three of these plants which require 

 a very dry atmosphere, and it is probable that others exist in other 

 countries. " These are Dendrobium lemulum, Brown, an Epiphyte 

 uniformly found upon the rugged trunk of Eucalyptus resinifera, or 

 Irou-Bark, in the open very dry forest grounds of the older colony at 

 Port Jackson ; Cymbidium canaliculattim, Brown, which of late years 

 has been observed beyond the tropic both at Moreton Bay and still 

 farther to the southward at Hunter's River, growing upon the prin- 

 cipal limbs of several of the Eucalypti in the dry open shadeless forest. 

 These two Epiphytes flourish most luxuriantly in an extremely dry 

 atmosphere, and flower usually in the summer season in their native 

 wilds, the high temperature of which is oftentimes greatly increased 

 by the blighting hot winds which not unfrequently prevail at that 

 period from the north-west. The third is Dendrobium undulatum of 

 Sir. Brown, a handsome species, originally discovered by Sir Joseph 

 Banks at Bustard Bay, and which has been lately found on barren 

 hills naturally clear of timber upon the banks of the Brisbane River 

 at Moreton Bay, where the plant forms tufts on bare rocks exposed 

 to the full heat of the sun, which during nine months of the year is 

 very considerable on that part of the coast." 



In many cases a much lower temperature than that hitherto spoken 

 of is natural to these plants, and there are some instances where they 

 are naturally accustomed to rigorous weather. In America their 

 favourite station, according to Humboldt, is in the gorges of the 

 Andes of Mexico, New Granada, Quito, and Peru, where the air is 

 mild and humid, and the mean temperature is 63 to 67 Fahr. (17 to 

 19 Cent.). In these localities they are so abundant that, according 

 to the authors of the ' Flora Peruviana,' above 1000 species might be 

 found in Tarma, Huanuco, and Xauxa alone. It is therefore not 

 surprising that one species, Epitlmdrum conopteum, should advance as 

 far to the northward as the rice climate of Florida, where it grows 

 on the bark of Magnolia glauca ; nor that others should be found in 

 the damp maritime parts of the government of Buenos Ayres. But it 

 is more remarkable that an Oncidiv.ni nubiyenum should occur at the 

 height of 14,000 feet on the mountains of Peru, and that other species 

 should, upon the authority of M. Descourtilz, be able to bear without 

 difficulty the cold glacial winds of the high serras of Brazil. The 

 lame peculiarities occur in the eastern, world. Reinwardt speaks of 

 great quantities of Orchidacect in the Storax and Laurel woods of 

 Java, growing along with Nepentha, Rhododendrons, Magnolias, and 

 Oaks, in a zone of vegetation whose lower limit is 3000 feet above 

 the sea. Dendrobium nobile, Renanthera coccinea, and some others, 

 bear the periodical cold of Canton, where it occasionally freezes; 

 llcndrobium catenaium and D. moniliforme occur in Japan as far north 

 as 37 or 33, or the parallel of Lisbon, and are periodically subject 

 to a very low temperature ; and Dr. Royle met with the deciduous 

 Codogyna and Dendrobium alpettre on the Himalaya Mountains at the 

 height of 7500 feet, where snow sometimes lies in winter for a week 

 or more. To the southward they not only occur in the latitude of 

 Port Jackson, where the mean temperature does not exceed 66 6', 

 but even in much higher latitudes. The beautiful little Gun-ma 

 Auttralii grows on the branches of shrubs in Emu Bay, iu Van 

 Piemen's Land, in about 41 S. lat. ; and Earina mucronata extends to 

 45 45' S. lat., in " the very permanently damp woods which clothe 

 the shores of Dusky Bay in New Zealand," where it was originally 

 observed by Forster in Cook's second voyage, and where it has since 

 been met with by Mr. Cunningham, whose words we quote. 



Such are the more important data that we possess to guide us in 

 the cultivation of Orchidaceous Epiphytes ; the result of which is, 

 that they are kept in this country in stoves the air of which is main- 

 tained in a state of constant moisture, and at a temperature varying 

 from 56 to 90 or more. The requisite uniformity of their atmosphere 

 is provided for by keeping the houses but little ventilated, and the 

 glass of the roof well puttied at the junction of the squares. Shade 

 is secured either by moveable laths or by a screen of netting or coarse 

 canvass, or by some such contrivance ; some even grow their plants 

 in a house exposed only to the north, but it does not appear that 

 this plan is a good one ; for it is an object not only to exclude excessive 

 light, but also to be able to admit it if requisite, and this cannot 

 happen in a hothouse with a northern aspect. 



The soil in which the plants are made to grow is peat or some other 

 kind of decayed vegetable matter, thoroughly drained, and yet so 

 compact as not to be liable to become dry by excessive loss of water. 

 In many cases it is found advantageous to make the plants grow upon 

 the apex of a truncated cone of earth rising several inches above the 

 rim of the pot. Certain kinds are suspended in baskets, or in frames 

 BO contrived as to be filled with moss and decayed vegetable mould 

 rammed in very tight ; and provided that precaution is attended to, 

 the caulescent drooping species, especially Dendrobiums and Vanda- 

 like plants, thrive admirably ; but in general it is found most advisable 

 to plant in earth in common garden-pots. Attempts have been made 

 to grow ome species on decayed dead wood, but they are generally 

 abandoned now ; nor have the trials to cultivate them on the branches 

 of living trees hitherto proved more successful. The orange-tree was 



employed for this purpose by Mr. Lance with great success in Surinam, 

 but in the hothouse it does not appear to suit them. * 



By attending to the natural habits of these plants, and observing 

 the precautions just pointed out, the management of Orchidaceous 

 Epiphytes has been brought quite within the skill of any good 

 gardener. There are however two or three capital points about which 

 cultivators entertain great difference of opinion. 



The first is temperature. Some allow the thermometer to rise to 

 100 and higher iu a summer's day, and never suffer it to fall below 

 65 ; the consequence of which is, that their houses are so unpleasant 

 that few persons can visit them to inspect the beautiful objects they 

 contain. Others keep the temperature of even midsummer down to 

 80 at the most, and permit the minimum heat to be low iu proportion ; 

 their houses are consequently cool and pleasant at all times. If we 

 must admit that the first practice is eminently successful with some, 

 so is the other most assuredly so with others ; and we entertain no " 

 doubt that in the end it will be the only method followed. 



The second question is the amount of moisture. Some form water- 

 tanks in their houses, the evaporation from the surface of which keeps 

 the air continually at the point of saturation ; others simply keep 

 the air sensibly moist by syringing or similar devices : the first is 

 accompanied by a high, the latter by a moderate, temperature ; in 

 this case also we incline to believe that the latter practice is the best. 

 The fact is that it may be reasonably doubted whether it is right 

 always to follow nature literally in what we suppose to be her practice, 

 and whether we ought not rather to adapt the management of our 

 plants to the new and artificial condition under which they are placed. 

 Keeping plants in a state of constant excitement by exposure to an 

 excessive climate is a certain means of weakening them in the long 

 run, and may be compared to keeping an animal always awake. It 

 may be very true that this may seem to happen in nature ; but does 

 it really happen ? Is it not probable that the long diurual darkness 

 of a tropical situation may be intended as a compensation for the high 

 excitement of daylight ? and are not we, with eighteen hours' daylight 

 in summer, in an essentially different position from what Orchidaceous 

 Epiphytes from equinoctial regions are exposed to in a wild state ? 

 Moreover, it can hardly be doubted that a moderate temperature is suffi- 

 cient for them, even if they can be made to bear an excessive climate. 



The third unsettled point is of another nature. In our hothouses 

 we often maintain a high temperature all the year round, keeping 

 our stove-plants growing from January to December. In nature this 

 hardly ever happens. If a country has no winter it has its dry 

 season, during which plants become more or less torpid. This is 

 quite the case iu all the countries inhabited by Orchidaceous 

 Epiphytes, with the exception of some of the temperate parts of 

 Mexico, where the climate is equal and mild. Should we not there- 

 fore give such plants, when cultivated, a similar period of repose ? 

 About this the opinions of cultivators are so much divided that we 

 cannot say on which side the majority of votes would go. Mr. Bate- 

 man calls attention to the fact, in his account of Colley's mission to 

 Guyana. " In consequence," he says, " of the unexampled length of 

 the dry season, scarcely an orchidaceous plant was seen in flower, or 

 a pseudo-bulb which had not lost its leaves. When however the 

 rains had commenced, that is, in the month of July, the Orchidacccc 

 were pushing rapidly into flower, as were also some of those collected 

 by Mr. Colley, which reached this country in as dry and shrivelled a 

 state as Dutch bulbs usually come over in. This may afford a hint 

 for their cultivation." 



And Henchman, in like manner, urges the circumstance upon the 

 consideration of gardeners.: 



" The atmospheric changes," he says, " are very great in tropical 

 climates ; and as I consider that OrcMdacece derive their main support 

 directly from the atmosphere, I think too much attention cannot bo 

 paid to the various changes by which they are iu their natural state 

 liable to be affected. One of the principal objects kept in view by 

 growers of Orchidacece appears to be the keeping up a regular heat in 

 the stove. Nothing can be more contrary to nature ; for in the tropics, 

 to a sultry day, with the thermometer standing at from 85 to 95, 

 succeeds a cool night and a cold morning, the thermometer falling to , 

 60 or 55 ; effecting in twenty-four hours a change of temperature of 

 from 20 to 30 degrees. During the dry season, periods of two, three, 

 and often extending to five or six mouths, the whole nourishment 

 derived by the Orchidacece must be communicated through the agency 

 of the tree to which they are attached, or from the atmospheric 

 moisture which is the effect of the action of the sun upou the dew 

 which has fallen during the night and morning; for the situations 

 generally occupied by Orchidacece preclude the possibility of the dew 

 reaching them in its descent; and slight though the moisture be 

 which is communicated through these channels to Orchidacece, it is 

 nevertheless sufficient to retain the vital principle in the pseudo- 

 bulb, though not sufficient to rouse it into action. The dry season 

 tten appears to act upon Orchidacece on much the same principle as 

 ou,r winter acts upon our trees, &c. It is for them a period of rest ; 

 and the pseudo-bulbs having been well ripened are ready, when the 

 wet season has given them a sufficient stimulus, to push forth 

 luxuriantly both leaves and flowers." Nevertheless some of our 

 best gardeners object to the plan of periodical resting ; and, it must 

 be added, appear to succeed without attending to it. 



