88 DB. B. SPEUCE OK EQUATOBIAL-AMERICAJ^ PALMS. 



layer li line thick ; (3) an equal thickness of similar but stouter 

 fibrous laminae adhering into a woody mass or outer shell ; (4) the 

 true endocarp, | line thick, black, bony, and with difficulty sepa- 

 rated from the outer envelope. 



The thin mesocarp of Iriartea exorrhiza is separable into two or 

 three fibrous layers, and that of (E)iocarpus minor into many such 

 layers. In the latter the laminae are flabellately veined, the 

 simple veins (fibres) radiating from the base to the apex. 



In Leopoldinia minor and L. Fiassaba^ besides the fleshy meso- 

 carp next the skin, there is an endocarp consisting of a great 

 many separable layers, whereof the outermost is entirely com- 

 posed of stout woody interwoven and anastomosing veins or fibres; 

 while the inner layers get gradually thinner, and the veins merely 

 cross without anastomosing, until the innermost is a delicate almost 

 veinless membrane. 



It might safely be inferred, from a priori considerations alone, 

 that the layers of the pericarp were modified leaves ; but their 

 true homology is made most clear by the structure of the fruit of 

 Leopoldiniaj where the laminae are exactly miniature counterparts 

 of the reticulated petiole-sheaths. In the genus Bactris the cha- 

 racteristic striae of the leaf-sheaths are reproduced on the epicarp, 

 and the aculei on the endocarp, as I shall have to describe more 

 fully in the sequel. The pericarp, then, is composed of imbri- 

 cated rudimentary leaves, whereof the blade is undeveloped or 

 reduced to a minimum. Even the raphe, with its thin white veins 

 netting over the testa, is but a modified leaf-sheath, a sort of 

 ovular bract subtending the ovule from its first appearance, and 

 growing with its grow^th. 



§ 7. The Scales of the loricated fruits of the Trihe LepidocaryiTKB 



are rudimentary Leaf-hlades, 



But in Mauritia and other Lepidocaryince the carpophylla, or 

 fruit-leaves, consist not only of a sheath, but of a rudimentary 

 blade, at first a minute erect scale, but after fertilization becoming 

 retrorse, and clothing the ripe fruit with shining rhombic scales 

 that give it a beautiful loricated or tessellated appearance, and 

 liken it to a fir-cone. Dissection affords ample proof that these 

 scales are really the homologues of the fan-shaped leaf-blade of 

 Mauritia, 



