448 Proceedings of the British Association. 



Saturday. 



The attention of the Section was this day devoted to Botany. 



Chevalier Schomburgk read a series of papers, the first of which was 

 entitled ' Description of Alexandra Imperatricis, a new genus of 

 l'apilionacese.' — This tree, in appearance, is one of the most beautiful 

 and gorgeous of the family of Leguminosse, and was discovered by the 

 author at the foot of the northern ridge of sandstone mountains in the 

 pluvial basin of the River Cuyuni, in Guiana, and reaches a height of 

 from 100 to 120 feet. The flowers are developed directly from the trunk 

 and woody branches, in large clusters, and the racemes, pedicels, and 

 calyces are of rich crimson, the petals bright orange, striped with 

 crimson, the vexillum of a deep purple, and ascending. The pod is from 

 18 to 20 inches long, and contains several seeds. 



The President inquired what was the largest tree the Chevalier had 

 observed in the forests of Guiana. — Mr. Schomburgk replied, the Mara 

 excelsa was the highest tree. 



The next paper by Mr. Schomburgk was a description of a new 

 species of Barbacenia. — This plant grows on the table-land from which 

 Mount Roraima rises. It reaches frequently a height of 10 or 12 feet, 

 branching in a dichotomous manner, and bears a number of flowers, 

 which, in their appearance, are liliaceous, and 5 to 6 inches long. They 

 are, outside, of a delicately purplish hue, and deliciously fragrant. It 

 differs from the species of hitherto described Barbacenise, in possessing 

 18 fertile stamens. The difference in the number of stamens is not, 

 however, allowed to be generic in allied species of Vellozise, and, there- 

 fore, the author has placed this plant with the Barbacenise. 



' On the Ophiocaryon paradoxa, the Snake-nut tree.' — In a former 

 communication Mr. Schomburgk had called the attention of naturalists 

 to the peculiar seed of this tree. The seed is covered over with a mem- 

 brane, which, on being removed, presents the embryo elongated and 

 twisted in a spiral manner, so as to give it the form of a snake. From 

 a recent examination of the flowers of this tree, the author had found 

 that it belonged to the natural order Sapindacese. The embryo is 

 twisted in other members of this order. 



On the Calycophyllum Stanleyanum. — There are several genera of the 

 natural family of Rubiacese, as Calycophyllum, Musssenda, Pinkneya, 

 &c, where one of the teeth of the calyx expands into a coloured 

 petioled leaf, of a membranaceous texture. In this tree it is very 

 remarkable ; and as these bract-like organs are of a rose colour, they 

 give a very beautiful aspect to the forests where they grow. This 

 appendage only grows after the flower has dropped off, and develops 



