so 



SCIENCE-GOSSIP. 



full)- distended lar\a approximates ven* nearly to that 

 of the tindistended pupa, and that in the case of the 

 distended pupa, may actually exceed the undistended 

 female in size. This is probably accounted for by the 

 accidental individual variation of the specimens 

 measured. 



No growth is observable when ticks are kept in 

 confinement on damp moss. It is probable therefore 

 that length of body is only acquired by distension on 

 the host by suction of blood. Other development, 

 such as size of shield, rostrum, length and number of 

 legs, are gradually formed after repletion, and after 

 leaving the host. When these are complete the 



metamorphosis takes place, the tick then casts its skin 

 and advances a stage in its existence, and at once seeks 

 a fresh host. 



Larvae hatched on August 4th last year, and kept 

 in a bottle are still alive and active on June 7th, 

 though no growth whatever is perceptible. For many 

 weeks past the damp moss has been removed, and 

 they have had nothing but damp sand and blotting 

 paper, from which it would seem impossible for them 

 to have derived any nutriment. 



I^'g- 13 g"'es a female and her eggs from a 

 photograph. 



( To be continnea. ) 



FLOWERS ON OLD WOOD. 



By Eleonora Armitage. 



A N interesting and suggestive letter was written 

 ^^ by Dr. Augustus Henry from Yunnan, to 

 Mr. Thistleton Dyer, which was published in 

 "Nature," of November 17th, 1898. It contains 

 the following sentences: — "In many of the 

 Mengtze and Szemao trees and shrubs, the flowers 

 occur on the branches below the leaves, and not 

 on the peripheral surface of the tree, as 'in ordi- 

 nary cases. Many lianas have this peculiarity. 

 These are all forest plants, and I think the expla- 

 nation is that in forests there are two surfaces open 

 to insect visitors, the top of the forest and the 

 bottom. Some trees and shrubs and climbers can- 

 not get to the top, so they have their flowers at the 

 bottom. But, of course, this explanation is only 

 a guess." Dr. Henry goes on to mention as an 

 example, Mucuna sem2iervirens, a liana interlaced 

 among trees, nearly 200ft. by looft. ; " The main 

 trunk of the climber close to the ground was 

 covered with flowers, which were easily visited by 

 thousands of insects of all kinds." 



It is desirable to have an explanation of the 

 reason why the flowers of some tropical trees are 

 thus borne on the old wood. It is one of the most 

 striking peculiarities of tropical vegetation, and 

 forces itself upon the observer, rather in the fruit 

 than in the flower, the former being usually the 

 more conspicuous. Such, at any rate, has been 

 my own impression, when studying West Indian 

 vegetation. The explanation suggested by Dr. 

 Henry, though only as a guess, does not alto- 

 .gether commend itself to me. 



• It may be well to examine some other and 

 familiar instances. A large forest tree, Coiirojcpita 

 guiantnsis, or " cannon-ball " tree, bears a suc- 

 cession of flowers around the lower part of the 

 trunk, on peduncles of varying length. From these 

 peduncles hang numerous fruits in different stages 

 of growth. When mature they consist of large 

 round woody capsules, from which the tree derives 

 its vernacular name. If these fruits were borne on 

 the distal -portions of the branches, their weight 

 would cause the branches to be bent down and 

 distorted, and probably broken off. 



Another case is that of Theohroma cacao, or 

 cocoa tree, which is a rather low tree, much 

 branched, and spreading. Its flowers are borne 

 on peduncles an inch long, scattered on the trunk 

 and larger branches. The oval fruits usually 

 measure about seven or eight inches long, and 

 eight or nine inches in circumference, and are 

 borne in large numbers, ripening in succession. 

 Their presence on the young twigs would be a 

 source of danger to the latter. 



Again, Crescentia cujete, or the calabash, is a 

 tree of moderate dimensions, bearing its flowers 

 on very short peduncles on the trunk and older 

 branches. At the same season, fruits may be seen 

 on the tree of varying sizes, from that of an acorn 

 to the large, heavy, spherical fruits, some of which 

 measure over twentv inches in circumference. It 

 is unnecessary to indicate the result to a young 

 branch if a fruit liearly the size of a football were 

 hanging on it, when the trade-winds blow strongly. 



Other examples might be adduced, but w-ould 

 take up too much space. 



The .suggestion, that the facts sketched above 

 have more to do with the force of gravity than with 

 insects, is put forward with diffidence, in the hope 

 that it may call forth a real solution of the problem. 

 It does not profess to clear up the whole question, 

 as it only applies to the large-fruited examples, 

 and not to others with a similar floral habit ; for 

 example, Ficiis, where the fruit is not so large. 

 It is not difficult to theorise on this subject, and 

 to imagine a stage in the early history of one of 

 these plants, when the flowers were borne normally 

 on the young wood. A slight increase in the 

 weight and dimensions of the fruit, if unaccom- 

 panied by a corresponding strengthening of the 

 tissues of the branches, would lead to the snapping 

 off of the latter. The plant would be compelled 

 to develop dormant or adventitious buds on the 

 older portions of the branches and stem, to replace 

 those that had been destroyed. Such plants as 

 were thus able successfully to resist the ravages of 

 wind and rain might, after many generations, take 

 on this habit and renounce their former one- 



