320 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Leaves, and in one form, that called Edgeicorthii, the heart of the plant 

 consists of a compact rosette of small sessile leaves, while placed on the 

 circumference are many very large ovate-elliptic leaves, horne on petioles 

 3 to 6 inches long. Lastly, the flowers may be solitary axillary, or 

 crowded within the axils, on either an exceedingly short or a greatly 

 elongated common stalk(fig. I'd, a'). One variety, scapigera, has a whorl 

 of petiolate, perfectly formed, but minute leaves, in place of the bracts, 

 surrounding the umbel of long pedicels. Among the spathulate-sessile- 

 leaved forms, one which Wallich named nana has linear-oblong sharply 

 toothed (erose) leaves, and usually large solitary flowers. From this form 

 the transition is almost imperceptible into P. Stirtoniana and P. Hookeri. 

 These might in fact be viewed as Alpine states but for one circumstance, 

 namely, that while the mouth of the flower in P. petiolaris is open and 

 never obstructed by an annulus, both these Alpine plants have the throat 

 constricted by a distinct annulus. Whether this is only a special sexual 

 adaptation to facilitate fertilisation or is a specific structural peculiarity, 

 I cannot at present say. I have accordingly retained them as species, but 

 P. p>etiolaris varies so remarkably that it would be no great stretch of 

 imagination to uphold the forms mentioned as only alpine states of the 

 protean species P. vetiolaris. 



In point of colour of flower there is less variability than in shape of 

 Mower, form of leaf, and degree of mealiness. The alpine states have as 

 a rule much larger flowers than those of lower altitudes. And what is 

 more surprising still, while the low-level forms are seen to originate large 

 clumps, within crevices of rocks in damp situations or even under the 

 spray of waterfalls, the alpine forms prefer the shade of bamboo or pine. 

 They invariably form large clumps, often a foot or more in diameter, and 

 are seen very frequently as one mass of bright rose-purple to pale lilac 

 flowers with yellow throats. But there is still another circumstance that 

 I think it is well to mention. The whole of the clumps in one neighbour- 

 hood flower simultaneously and have repeated flushings throughout the year. 

 On April 20 I passed along the Toungloo range in Sikkim when P. petio- 

 laris was a blaze of flowers (fig. 73, a). I returned twenty days later along 

 the same path and could not discover a single flower. I have collected it 

 in flower from March to September, though it is best in May and June. 



But, gentlemen, I have gone into these details with P. pctiolaris 

 because I think it is a much-neglected beautiful species. It sports 

 almost too freely, is perennial, and easily grown if liberally supplied with 

 water or planted alongside of limestone rocks. I have another reason : it 

 is very largely representative of the series with which I am at present 

 dealing. To understand them fully, however, it is desirable that I should 

 classify the pet ioh iris section a little more in detail. There may be said 

 to be two great subsections : — 



1. Leaves glabrous or nearly so, and ovate-spathulate to subrotund, 

 sheathing. The species are P. petiolaris in all its forms, also P. 

 Stirtonia/na and P. Hookeri. Then a special group that have large 

 sheaths on an erect stem, viz. P. pulchra and P. Dyeriana. Lastly two 

 plants, P. Clarkei and /'. replant, that I place here because of their being 

 glabrous N.W. Himalayan forms, but they might otherwise more naturally 

 be assigned positions in the set that follows. 



