70 



There are differences in the styles as regards length, some being well protruded 

 beyond the stamens. The stigma also may be punctif orm ; on the other hand it may 

 be more or less capitate or dilated. The stigma may be protected by fitting, as if 

 moulded, into the top of the operculum. In other words, the operculum may act as a 

 sheath to the stigma. This is readily seen in species with large flower-buds such as 

 E. pyriformls and E. macrocarpa. I will return to the subject when dealing with the 

 organs concerned. 



C— HYBRIDS AND ABERRANT FORMS. 



The hybrids already and to be described are interesting for the reason that 

 they may be assumed to be incipient species, and their history will be watched in the 

 future. 



I look Upon these hybrids as subordinate species, and I would gladly give them 

 names to indicate inferiority (in botanical rank) to the ordinary species. But it seems 

 to me that I have no choice between naming them like ordinary species, or continuing 

 to refer to them by circumlocution, which is in the highest degree inconvenient. 



One must not rely too much on the plates, in this and the next Part, which, of 

 course, can only display morphological characters. One must consider the other 

 characters referred to in the text, and, indeed, on consideration of these, the botanist 

 who suggests hybridism as an explanation, has pointed out the differences from the 

 species he considers it most closely to resemble, and yet to substantially depart from. 



There are pitfalls in assuming a species may be a hybrid, e.g., E.amplifolia Naudin. 

 In this case a plant showed characters sufficiently different from E. tereticomis for 

 Naudin to note an undescribed species. He made the natural mistake, however, to 

 attribute the differences to hybridisation, when, as a matter of fact, his French Algerian 

 plants arose from seeds of Australian plants sent as E. tereticomis. 



There is another aspect of the question of the ever- varying morphological aspect 

 of a species. Variation in Eucalyptus (and, indeed, all other genera) is going- on all 

 around us. I have in mind coming across in a E. saligna area a tree with very rough 

 flaky, exfoliating bark, similar to that which is usually seen to but a very small extent 

 on the butts of trees of that species. The buds and fruits seemed to be similar to those 

 of the rest of the salignas about. But might it not have been that the tree was under 

 the influence of saline conditions of soil? We know that E. botryoides, which sometimes 

 has the organs so similar to those of E. saligna, that we say they "run" into each 

 other, that is to say, it is very difficult and perhaps impossible to separate them on 

 morphological grounds, and it is a rough-barked species and often grows in soil more or 

 less saline. Perhaps this rough-barked saligna is evolving into botryoides, and that the 

 rough, exfoliating bark is an expression of intolerance to salinity. 



A perfectly smooth gum of any species is an ideal ; indeed, what we call " typical " 

 barks of any class are ideals ; they vary, and we try to explain the variation, and, 

 when the variation has proceeded far, we cut the knot, and constitute a new species. 



