1923] WILSON, THE HORTEXSIAS 235 



secondary veins arcuate, raised beneath; petiole stout, fleshy, 1.5-6 cm. 

 long, glabrous, flattened above. Inflorescence a much-branched, corym- 

 bose, terminal globose head from 15-20 cm. and more through, either sub- 

 sessile or distinctly peduncled, rhachis glabrescent, puberulous or more 

 or less densely clothed with short gray appressed curled hairs; flowers 

 pink to blue, sometimes white, sterile, with 4 spreading petaloid sepals 

 of various size and shape, acute or rounded, entire or notched with few 

 scattered male or apetalous abortive female flowers. 



This is the familiar Hydrangea with globose heads of sterile flowers of 

 varying shades of pink and blue. One of the most widely cultivated and 

 best-known exotic plants. It has been cultivated for centuries in the 

 Orient, yet its origin has escaped notice and remained unknown until now. 

 It is simply an anomalous condition of a littoral plant very common on 

 the shores of the Boshu peninsula in central Hondo, on Oshima or De Vries* 

 Island, on Hachijo and others of the seven isles of Idzu, described in detail 

 below under the name of H. macrophylla var. normalis. Where it origin- 

 ated or by whom it was first found and brought into gardens remains a 

 mystery. Very likely it was by some wandering Buddhist priest or 

 acolyte but we shall probably never know. That such a striking plant 

 with splendid flower-heads should spread far and w r ide among the flower- 

 loving peoples of the Orient should occasion no surprise. Where any 

 remarks on its possible origin have been made in western literature China 

 has been surmised as its native country, probably because so many fine 

 plants have come to us from that land. In this case, however, the credit 



belongs to Japan. 



The replacing of the ordinary flowers by sterile flowers having petaloid 

 sepals occurs in several species of Hydrangea. It is found in the Japanese 

 H. paniculata Sieb. and in the American H . cinerea Small and H. arborescens 

 Linn. In China I have collected wild specimens of H. strigosa Rehd. with 

 globose heads of neuter flowers. It is probable that this character can 

 and does appear as a sport in many species of Hydrangea. Also it occurs 

 in several species of Viburnum, and Thunberg doubtless had in mind the 

 sterile form of Viburnum Opulus Linn, when he referred this Japanese 

 plant to the genus Viburnum. Thunberg's description is quite clear 

 and De Cartdolle without hesitation refers it to the genus Hydrangea but 

 does not suspect its identity with //. Hortensia Sieb. which he had de- 

 scribed on the same page in his Prodromus. The most remarkable thing, 

 however, about its name is the fact that, though many authors have dealt 

 with the plant and several specific names have been established in common 

 usage for it, apparently no one has gone to the trouble of finding out what 

 Thunberg's Viburnum macrophyllum really was. For many years the prob- 

 lem of the origin of this plant has greatly interested me. In fact, during 

 all my travels in the Orient I was on the look-out for the wild parent. 

 Yet its discovery in March, 1917, was as surprising as it was welcome. The 

 evidence was plain and conclusive though it seemed incredible that the 



