VOL. LV.— No. 3,071. 



SATURDAY. Sl.PTKMBEE 7, 1912. 



THE 



GARDENERS 



5 



MAGAZINE 



NOTE OF THE WEEK. 



Epiphytes and Parasites. 



In the great struggle for existence 

 which, in the course of incalculable teons 

 of time, has led to the evolution of in- 

 nunierahle forms of plant and of animal life, 

 the result, in the former, has been the 



of many nlants which live 



production 

 upon others, 

 attachments 

 ones, or as 

 nourishment 



many plants 

 both as simple 

 or epiphytal 

 deriving their 

 from their in- 



voluntary hosts, thus consti- 



To 



tuting 



true 



the former 



parasites, 

 class 



an enor- 



number of orchids, 

 mosses, and other 

 belong, their exist- 

 ence being fostered by con- 

 warmth 



mo us 

 ferns 



genera 



genial conditions of 



moisture, particularly 



which enables 



and 



the 

 their 

 and 



latter, 

 seed: 



to 



develop 



of that 



germinat-e 

 without the 



soil which 



presence 

 the great majority of plants 

 require. The roots com- 

 mence by penetrating cre- 

 vices in the bark, and 



as 



the plant develops, it often 

 does so in such a manner 

 that leafy debris accumulates 

 around it, so that in time 

 it derives sufficient nourish- 

 ment in this way to form, in 

 tropical humid regions and 

 in forestal shade, huge and 

 flourishing specimens, as are 

 exemplified by many of our 

 finest orchids. Most of these, 

 in their native habitats 

 found on trees 

 tion with ferns 

 epiphytes. Among the ferns 

 of the epiphytal class, the 

 most prominent are pla- 

 tyceriums, or stagshorn ferns, 

 which bear 



are 



in associa- 

 and other 



two kinds of 



always the case in Nature however, there The mistletoe, for iiistnmv, belongs to the 

 are grades and grades of evolution, and former category, .since it produces foliage 

 the epiphytal character varies accordingly containing chloropliyll, which enables the 

 in degree. Thus, in our own familiar ivy, 

 we see adventitous roots developed, which 

 assist it to cling to its support, though 

 mainly dependent upon the soil for its 

 nourishment, while an immense number 

 of climbing plants use the robuster vege- 



tation to aid their ascent, and produce no the unha^jpy plant which it invades. 



OthiM- paiasitic ]>lants tlirivo 

 upon the roots ot tbt^ host 



. , , . plants, as does the orobanche, 



oi" broom rape, the lathra\'i or 

 tootliwort. and others. 



}*lant to contribute something to its own 

 growth^ though mainly <lepen(h'!ii upon 

 the host. The dixhliM*, on tli,. oiIkt 

 hand, provinces only rudimentarv leaves, 



* *j 7 



associate<l with an abundance of flowers, 

 and derives its sustenance entirelv fro 



The 



example 



is Kaffle.sia 



most extraortlinarv 

 of this type 

 Arnoldj, a tropical para- 

 site, which grows on tree 

 roots^ and produces no 

 leaves at all, but only im- 

 mense brown flowers very 

 fleshy, and as much as a yard 

 in diameter. 



of tlic ni(»st 



This is one 

 curious plants 

 known, sin -o it lias a strong 



carrion-like odotu . wliich in- 

 ducesdeliKkHl flies to lay their 

 eggs in it, the resulting gru])s 

 ix^ng doomed to starvation 

 by the absence of proj^er 

 foml, a double instance of 



plant tergiversation, 

 vast number of 



A 



plants, 



mainly fungi, support them- 

 selves parasiticallv. in the 



MR. J. DUXCAX PKAli^SON. 



fronds 



VIZ. 



large shield-like, barren ones, 

 which grow perpendicularly, and are ad- 

 mirably adapted for the lo<lgment behind 

 them of leafy debris, while the fer- 

 tile ones are bluntly forked, and spring- 

 ing from the central axis of growtli hang 

 pendulously downwards, the better to 

 scatter the spores with which the backs of 

 these terminals are literally coated, 

 kinds of ferns, such as davallias, cover 

 the tree trunks with their creeping 

 I'hizomes, and, in particularly humid habi- 

 tats, many si>ecies of filmy ferns do the 



Othe 



r 



same, not onlj- on trees proper, but also 



trunk-forming ferns as well. As is entirely, from the sap contained therein. 



such roots, but only tendrils or clinging 

 foliage, or by mere spiral twisting main- 

 tain their hold without being epiphytes at 

 all in the acceptetl sense, which implies 

 an entire independence of soil support. 

 Epiphytes therefore indi-cate by their very 

 nature the need for moist aerial condi- 

 tions, and successful culture is, conse- 

 quently, largely dependent upon such pro- 

 vision. Parasitic plants, on the other 

 hand, demand no such environment, since 

 their roots, or root equivalents, penetrate 

 the substance of the host plants, and de- 

 rive their nourishment, either partly or 



torm oi diseases, the potato 

 disease, for instance, being 

 due to the attack upon, and 

 permeation of, the tissues 

 by a fungoid plant, Perono- 

 spora infc^tan.-;, while an- 

 otlier fungal host 4h^rives 

 sustenance from dead jthuit 

 material. These, however, 

 belong to neither e])ip}iytes 

 nor parasites, but to the 

 tril>e of saprophytes to which 

 living plants pay no toll, 

 though it is suspected that 

 some of these are not over-particular, and 

 sometimes contribute to their larder 

 by invading living tissues as well. Nature^ 

 in fact, nev;»r <lraws hard and fast lines 

 between kindred organisms, and although 

 man mav classifv her creations, there are 

 always forms on the border lines he en- 

 deavours to define, which are not exactly 

 either the one thing or the other, and 

 baffle his ingenuity. 



Mr. J. Duncan Pearson, whose 



portrait we have the pleiisure of giving 

 her*Hvith. is a memlxM- of the firm of 

 Messrs. J. R. Pearson and Sons, whose 



