BOTANICAL EXPLORATIONS OF MR. SPRUCE. 199 
contains the only flowers in each branch that fertilize the females in their 
neighbourhood, and I believe (although I have not yet tried the experi- 
ment) that if all these original flower-heads were cut off the plants 
would produce no fruit; for in the plants I have seen, the two flowers 
usually fertilized were the flowers that grew side by side, and in close 
proximity to this particular head of male flowers. It is true the flower- 
heads of the secondary peduncles sometimes have the ovary more or 
less swollen, and occasionally the seeds may be fertilized, but if the 
seeds are fertilized by the pollen of their own males, it is an exception 
to the rule. Tt is not at all improbable that the pollen form an original 
head of male flowers somewhere else on the plant, and in a less ad- 
vanced state may effect this. 
Since writing the above I have examined several other species of 
Euphorbia, and traces of the flower-heads containing males alone, 
could be distinctly seen. 
BOTANICAL EXPLORATIONS OF MR. RICHARD SPRUCE, 
We are glad to announce that Mr. Spruce has safely returned to England, 
after an absence of fifteen years in South America. Previous to his departure 
from Europe, this enterprising traveller had investigated the botany, especially 
muscology, of Yorkshire and the Pyrenees. He left Liverpool on the 7th of 
June, 1849, and reached Pará, Brazil, on the 12th of July. After spending 
three months in exploring the environs of that city, he ascended the Amazon 
to Santarem, at the mouth of the Tapajoz, and in November of the same year 
went seventy miles further up, to Obydos, where the Amazon is at its narrow- 
est and deepest. Starting from Obydos, he explored the Trombetas and its 
tributary, the Aripecurd, as far as the cataracts of the latter, in lat. 0° 47’ N., 
fixing five latitudes by astronomical observations, and making a map of those 
previously unknown rivers. Returning to Santarem in January, 1850, he re- 
mained there exploring the lower part of the Tapajoz and adjacent parts of the 
Amazon until October, when he started up the Amazon for the Barra do Rio 
Negro, where he arrived after a voyage of sixty-three days, thirty whereof 
were spent in the channels to the south of the great island of Tupinambaráua. 
The greater part of the year 1851 was occupied in studying and collecting the 
rich vegetation of the lower part of the Rio Negro, and of the Amazon for a 
few days’ journey up; and in November he started for the head-waters of the 
Rio Negro, in a boat of about nine tons burden, which he had fitted up ex- 
pressly with that object. Early in January, 1852, Mr. Spruce reached the 
