IRISH GARDENING. 



shrubs, w^ll known in gardens. In ^'e\v Zea- 

 land tliose have colonized the country from sea- 

 level uj) to alpine heights of 0,UUU feet. Those 

 which grow low down iiave large iiat leaves 

 lilie I', spccid.sii (whicii is cnuliiied to sea clilTs) 

 and r. mavrunra ; but as \\i' iisrcud tlie liills 

 the intlueuce of the mountain e'liiiiate make^^ 

 itself felt. The necessity tor c'iiecking loss of 

 water by the reduction of tlie vegetative parti 

 becomes pressing, and as tlie higher regions are 

 approached the leaves become smaller and 

 smaller, till at ."),()00 feet we find only such 

 forms as l'. vujin^^Hvides, ]'. aaUcoiiiitiiilcn, \ . 

 I i/cupudioides, in whicli, as their names suggest, 

 the leaves are reduced to tiny intricate scales, 

 among whicli llie white X'cronica llowers look 

 strangely out of place. These obser\utions may 

 be condensed into a rule for horticulturists, 

 applicable with few exceptions to the genus 

 \'eronica, and generally true in genera of wide 

 variation in leaf-size, though of course excep- 

 tions occur. The smaller-leaved a species in 

 such a yenas /s, the hardier it maij be expected 

 to prove, and the drier the situation which it 

 enjoys. 



Let us take just one more genus — Saxifraga. 

 The Saxifra-ges are an enterprising race. They 

 have made their way right round the Northern 

 Hemisphere, and into all kinds of places^ 

 swamps and dry rocks, low meadows, deep 

 woods, and alpine peaks; they have penetrated 

 far within the Arctic circle, and have pushed 

 down the chain of the Andes into South 

 America, but they have not achieved all this; 

 colonization without having been profoundl_]y' 

 modified in the process. One small group, the 

 section Piol)ertsonia, is interesting as being ex- 

 clusively Western European, two of the three 

 species comprising it being characteristic plants 

 of Western Ireland — namely, S. lUHbrosa 

 (London Pride) and S. Gcuni. x\long with the 

 third species, S. cuneifolia, these have adopted 

 a characteristic habit and a sub-alpine habitat. 

 Another gi'oup which is mainly European and 

 sub-alpine includes the well-known Mossy 

 Saxifrages (section Dactyloides). These have 

 adapted a ({uite characteristic aljjine growth- 

 form, forming by repeated branching dense 

 cushions of innumerable small leaf rosettes, a 

 plant-form excellently suited for resisting ex- 

 tremes of cold, heat, drought and wind. But 

 they are shade-plants, found mostly on damp 

 rocks. For a group which has accommodated 

 itself to hot, dry alpine rocks we turn to the 

 Euaizoonia, or Silver Saxifrages, which include 

 many of the highest favourites of cultivation. 

 These plants form tufts of dense rosettes of 

 narrow leathery leaves, which are characterized 

 by the presence of little pits filled with lime, 



to whicli tlirir pietty silvery appearance is due. 

 The lime exudes from the pits and sometimes 

 covers the whole surface of the leaf with a 

 hite deposit, the object of M-hicli is to protect 

 the sui'lace Iroiii inidiif loss of water. The 

 apparatus coiuiccli'd with this anaiigement is 

 most ingenious, showing a high degree ol 

 specialization f(.>r a life spent on di_\ rocks. 



Another section specialized for rock growth 

 is that named Kabschia, which yields many 

 species highly jirized in gardens, such as »S'. 

 iipiciihifd and S. sancta. There the alpine 

 c-ushiou form is very well developed, with the 

 associated branching of stems and diminution 

 of leaf surface, but the plants are better suited 

 than tlir similar Mossy Saxifrages for growth 

 in dry jdaces by having the leaves thick-skinned 

 ai^d tough, and the whole plant tightly packed 

 tdgether. In contrast to these, many of the 

 Nbrth American Saxifrages have taken to life 

 -iq damp meadows and swampy places, among 

 rank vegetation. These have developed into 

 C(|arse hairy herbs, with tall stems bearing in- 

 CGpispicuous flowers (such as *S. pennsylvanica), 

 ai^d they possess none of the beauty or interest 

 of the Aizoons or Kabschias. In China again 

 the Diptera section has developed on damp rock 

 ledges and shady woods, and presents a series 

 of delicate herbs, some of them very pretty, 

 with [lalmate leaves, and flowers which are 

 unique among the Saxifrages in bearing unequal 

 petals. In the well-known S. Fortunei, for ox- 

 arhple, there are three short petals, the remain- 

 ing two being long and pendent. The acme of 

 dataip-loving Saxifrages is reached in *S'. peltata, 

 a |)lant with great umbrella-like leaves on stems 

 a j^ard high, and a thick creeping rhizome cap- 

 able of flourishing if half the year under water. 

 This remarkable plant is confined to a few 

 mountain valleys in California, and was con- 

 sidered to be the sole representative of a dis- 

 tinct section till a few years ago, when a plant 

 raised at Kew from Chinese seed proved to be a 

 diminutive cousin of the Californian giant. The 

 general similarity of form between »S. peltata 

 and other ]dants of river banks, such as the 

 Butterbur (/'r/^/.s/'/cs ridyaris) again illustrate;? 

 the influence of the environment upon the 

 organism. 



Plagianthus Lyallii. 



In view of the reference, in the October 

 number of luisii (Iahdening, to the specimen of 

 Plagianthus Lyallii at Eowallane, a note as to 

 the plant may be of interest. 



It is now generally recognised that there -^ire 

 two forms of this species; one the typical plau<--, 

 whitish on the underside of the leal, soft and 



