A very dry
station apparently favours the presence of the female form. With some of the
other above-named Labiatae the nature of the soil or climate likewise seems to
determine the presence of one or both forms; thus with Nepeta glechoma, Mr. Hart
found in 1873 that all the plants which he examined near Kilkenny in Ireland
were females; whilst all near Bath were hermaphrodites, and near Hertford both
forms were present, but with a preponderance of hermaphrodites. (7/16. 'Nature'
June 1873 page 162.) It would, however, be a mistake to suppose that the nature
of the conditions determines the form independently of inheritance; for I sowed
in the same small bed seeds of T. serpyllum, gathered at Torquay from the female
alone, and these produced an abundance of both forms. There is every reason to
believe, from large patches consisting of the same form, that the same
individual plant, however much it may spread, always retains the same form. In
two distant gardens I found masses of the lemon-thyme (T. citriodorus, a var. of
T. serpyllum, which I was informed had grown there during many years, and every
flower was female.
With respect to the fertility of the two forms, I marked at Torquay a large
hermaphrodite and a large female plant of nearly equal sizes, and when the seeds
were ripe I gathered all the heads.
Pages:
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403