126 THE JOURNAL OF INDIAN BOTANt. 



what has been taken to be Wight's H. hirsutus has rather broader 

 leaves than Wight's illustration, (Ic. PI. In. Or. t. 2067) shows but 

 is probably the same species, and the illustration might have been 

 drawn from my plant. (Comp. the plate opposite). It would seem 

 therefore that Wight's H. hirsutus and perhaps also H. glaber, has 

 orange flowers on the lower slopes and blue flowers on the higher, 

 and that they are two varieties a glabrous and a hairy of one species. 

 A change from pink or purple to blue is common enough but orange 

 and blue are not as a rule I believe, interchangeable, a blue colour 

 being usually in the cell sap, but an orange in plastids. Possibly we 

 have in these four plants two pairs of Mendelian allelomorphs 

 segregating ; hair and their absence, and orange and blue colours. 

 Both forms were abundant where I found them, and growing side by 

 side. 



It would be interesting therefore to know whether there are any 

 cases known of a species having blue flowers in one place and orange 

 flowers in another. 



The flowers of Hydnocarpus alpinus Wtk are typically 

 dioecious. Recently I found near Coonoor a single male flower on a 

 female tree, with pistillate flowers and fruits above and below on the 

 same branch. Such an occurrence is probably not uncommon, though 

 seldom recorded. Davy and Gibson described*, the occurrence of both 

 sexes on the same plant of Myrica Gale a typically ' unisexual 

 dioecious species, and what, was more interesting, observed a change 

 from maleness to femaleness between one year and the next on more 

 than one plant. 



Ever since the discovery of chromosome reduction we have been 

 compelled to consider higher plants and ferns as never really sexual 

 at all, sex appearing only in the last divisions of the celte which 

 produce the pollen grains and ovule respectively. But where the 

 flowers are unisexual the visible ' sex ' may be dependent on external 

 conditions, and is known to be affected sometimes by parasites. The 

 object of this note is to call attention to this, for in India we have 

 many plants with unisexual flowers e.g. spp. of sterenlic, Terminalia, 

 Piper, Myristica and observations of these, from year to year, by those 

 in a position to make them, might lead to the discovery of the condi- 

 tions which affect ' sex ' (though if as seems likely sex is a Mendelian 

 character, only in heterozygous individuals) or in the relative numbers 

 .of male and female flowers, with results perhaps of both scientific arjd 

 economic importance. 



P. F. Fyson. 



* Davy, A. J., and Gibson, C. M. Note on the Distribution of Sexes in 

 Myrica Gale New Phtjl. XVI{lf)(7),}jp.U7.—loL 



