348 



THE GARDENERS' MONTHLY 



[August, 



ON THE RELATIONS OF HEAT TO TME 



SEXES OF FLOWERS. 



BY PROF. THOMAS MEEHAN. 



At the meeting of the Botanical section of the 

 Academy of Natural Sciences, of Philadelphia, 

 on April 9th, Mr. Thomas Meehan referred to his 

 past communications to the Academy showing 

 that in mona^cious plants female flowers would 

 remain at rest under a temperature which was 

 s,ufficient to excite the male flowers to active de- 

 velopment. Hence, a few comparatively warm 

 days in winter or early spring would bring the 

 male flowers to maturity, while the female flowers 

 remained to advance only under a higher and 

 more constant temperature. In this manner the 

 explanation was offered why such trees were often 

 barren. The male flowers disappeared before the 

 females opened, and hence the latter were unfer- 

 tilized. He referred especially to some branches 

 of Corylus Avellana, the English Hazel nut, which 

 he exhibited before the section last spring, in 

 which the male flowers (catkins) were past 

 maturity, the anthers having opened and dis- 

 charged their pollen, and the catkins crumbling 

 under a light touch ; but there were no appearances 

 of action in the female flower buds. There were 

 no nuts on this tree last season. The present 

 season was one of unusually low temperature. 

 There had not been spasmodic warmth enough to 

 bring forward the particularly excitable maple tree 

 blossoms. The hazel nut had not therefore had 

 its male blossoms brought prematurely forward. 

 He exhibited specimens from the same tree as laS't 

 season, showing the catkins in a young condi- 

 tion of development, only half the flowers 

 showing their anthers, while the female flower 

 buds had their pretty purple stigmas protruding 

 from nearly all of them. Mr. Meehan remarked 

 that his observations the past few seasons had 

 been so carefully made that he hardly regarded 

 confirmation necessary, but beheved the further 

 exhibition of these specimens might at least serve 

 to draw renewed attention to his former communi- 

 cations. 



EDITORIAL NOTES. 



MiCHAUx Lectures. — Among the most popular 

 of institutions is the Michaux Series of Lectures, 

 given by Prof. Rothrock in Fairmount Park, Phila- 

 delphia. The eminent botanist, Michaux, left a 

 sum of money, in trust, to the American Philo- 

 sophical Society for the promotion of botany and 



arboriculture, and a portion of the fund is devoted 

 to this purpose. They are so popular that often 

 there is scarcely standing room. The abstracts we 

 give were prepared for the Public Ledger. 



Reaioving Tendrils from Grape Vines. — It 

 has from time immemorial been considered excel- 

 lent practice to remove the tendrils from growing 

 grape vines. It seems scarcely credible that a prac- 

 tice so universal with the best grape growers, and 

 which hashitherto been unquestioned, should really 

 be a bad one. But this is what the Journal of 

 Horticulture has mustered up the courage to say : 



"We do not consider it a good plan to pinch off 

 the tendrils from the leading growths of young 

 vines so closely as is practiced by many persons. 

 We remember once noticing some thousands of 

 remarkably fine vines in pots in Mr. Rivers' nurse- 

 ry at Sawbridgeworth. The pots were standing on 

 the hot water pipes, and the growths trained about 

 18 inches apart up the roof above. The grower of 

 these vines was justly proud of his work. They 

 bristled with tendrils, some of them a foot long, and 

 nearly as thick as quills. From a few of the vines, 

 however, the tendrils had been pinched off closely, 

 with the object of noting the effect. Only a dozen 

 or so w-ere so treated, and in every instance they 

 were weaker than the others, which led the culti- 

 vator to remark: 'Depend upon it if you want the 

 vines to grow strong and well you must let them 

 put out their horns.' " 



An Interesting Arad. — In our last we gave a 

 sketch of a plant of the Arum family which climbed 

 trees and walls. We now give, in contrast, one 

 which does not climb at all — one from Central 

 America, introduced by Mr. Wm. Bull, Anthur- 

 ium insigne. It will be observed that while in the 

 former plant the leaves were scattered along a 

 slender stem, so that there may, perhaps, be but 

 ten leaves along a distance of ten feet, we have 

 here the ten leaves all from one central crown. We 

 often see this varying mode of growth on one tree. 

 For instance, on the pear tree or the larch tree, 

 there are long growing shoots and there are spurs. 

 There will be quite as many leaves from a spur in 

 one season as from the long shoot, and we learn that 

 a spur is nothing more than a long shoot which has 

 become so very much coiled up in its spiral growth 

 as to lose its elongated character. What occurs 

 on a single plant, in the instance cited, becomes a 

 distinctive character in other genera or species of 

 plants. At any rate, the manner of growth of this 

 Aroid is precisely that of a spur in a pear tree or 

 larch. There might seem no reason why it should 

 not elongate and have leaves along a scattered 

 stem, as in the Pothos, noted last month, when it 

 would probably form another species of Anthurium, 



