52 



HARDWICKE'S SCIENCE-GOSSIP. 



Having brought under notice several birds sup- 

 porting the theory that birds laying small eggs in 

 proportion to their size lay a greater percentage of 

 false-marked eggs than other birds, one bird must be 

 called in evidence against it, i.e. the cuckoo. This 

 bird most certainly lays a small egg, not more than 

 one-fourth the size it should do to be equal with 

 other birds of its size and weight, nevertheless a 

 cuckoo's egg marked at the smaller end is as great a 

 rarity as the "four-leaved shamrock ; " the writer has 

 never seen a trace of false marking in any of the 

 cuckoo eggs he has had the opportunity of ex- 

 amining. On the 3rd of July, 1884, the writer took 

 from the nest of a tree pipit an egg of the cuckoo so 

 immediately after it was laid that the albuminous 

 moisture with which eggs are covered when first laid 

 was not dry. In this case but little time could have 

 been taken up in the selection of a suitable nest : this 

 egg fairly blended with the pipit eggs, but was 

 slightly lighter in colour. 



The great immunity these eggs enjoy from false 

 marking is doubtless owing to the cuckoo being able 

 to colour its eggs at will, or perhaps more probably 

 by impression ; if it were not so, the bird would more 

 often be seen carrying its egg in search of a suitable 

 nest or suitable clutch of eggs in which to place it. 

 All the cuckoo eggs the writer has found and taken 

 fairly represented the eggs amongst which they were 

 placed. 



After all, it may be that it is the exclusive pre- 

 rogative of the Falconidce to colour their eggs at the 

 smaller end, and that all other eggs showing a similar 

 coloration, are the result of either permanent or 

 temporary physical defect in the bird producing 

 them. If permanent, it is probable that more false- 

 marked eggs would be met with. The long narrow 

 type of egg is not so frequently met with, rarely two 

 are found in the same clutch, excepting amongst those 

 of the tree-sparrow {Passer montanus). I much 

 regret not having any evidence as to the fertility of 

 these eggs, but it is to be hoped that the coming 

 season will bring to light many facts bearing on the 

 subject to which this paper refers. 



Joseph P. Nunn. 

 Royston. 



P.S. — Since writing the foregoing, I have exam- 

 ined more clutches of sparrow-hawk and kestrel 

 ■eggs, and found the 40 per cent, average fully 

 maintained. 



NOTES ON ECONOMIC BOTANY. 



By J. T. Riches. 



RUTACE/E (BUCHU).— This medicine consists 

 of the leaves of several species of barosma, all 

 obtained from the Cape of Good Hope, where they 

 are collected by the Hottentots, often adulterated 

 with other leaves, such as the leaves of Adenandra 

 uniflora and species of agathasmas. But of course 



there is one or more species which are said to yield 

 leaves of the greatest medicinal value, but as usually 

 sold in shops they are a mixture of two or three 

 species. The true officinal plant is B. betulina, B. 

 and W. {Diosma crenata, D. C). Decandalle ap- 

 plies this name, and this is figured by Stevenson 



Fig. 24. — Barosma serratifolia. 



Fig. 25.— Buchu Leaves, a, Barosma graveolens ; b, B. betu- 

 lina {D. crenata) ; c. B. serratifolia ; d, B. venusta. 



and Churchill as the true plant. The leaves are 

 about three-quarters of an inch long, coriaceous, 

 obovate, with a recurved truncated apex and sharp 

 cartilaginous spreading teeth ; flowers pink, ter- 

 minating the, branches. The leaves of chemists' 

 shops are sai'd to be the produce of this species, but 

 are very obviously a mixture. Other species are 

 collected, such as B. crenulata, Willd., figured in 

 "Bot. Mag.," pi. 3413, vol. lxii., with leaves about 

 one inch long, oval lanceolate, obtuse, minutely 

 crenated, five-nerved, smooth, dark green above, 



