416 Pomona College Journal of Economic Botany 



outward, appearing as adventitious roots; for it seems that the entire mass 

 of the vascular bundles of recent formation is endowed with a latent 

 potentiality of producing adventitious roots, whenever a portion of it is 

 able, under favoral)le conditions of ambient, to pierce an opening tlirough 

 the external cylinder. This is what happens in those palms wliicli produce 

 large masses of adventitious roots in the epigeous i)arts of their trunks, 

 for instance, in Thriuar ucndlandiaua and, more especially, in dnussin /)//«- 

 ccps among the Cuban palms, and, also, among the palms cultivated in our 

 country, viz., Washingtonia, Phoenix dactylifera, etc., when they meet with 

 suitable conditions of temperature and moisture. 



From the observations made above I am led to conclude, that the bulging 

 of the stem in palms is due to the same ordinary processes which cause the 

 lengthening of the vegetative cone in the normally developed stems, and it 

 apparently depends, not upon a secondary growth of the already formed 

 elements, but, while it is partly due to the greater number of fibro-va.scular 

 bundles produced (and, also, perhaps, to the greater diameter of their ele- 

 ments), yet, in a still greater mea.sure, it is the effect of the greater diameter 

 of the cells composing the fundamental tissue and of the larger intercellular 

 spaces, the increased diameter of the cells being obviously caused by the 

 accumulation in their interiors of a large quantity of starch grains, or of 

 nutritive fluids, all of which are due to the increased vegetative activity of 

 the plant, in the moment that precedes the beginning of the reproductive 

 period. 



This was, also, the opinion of Martius, who, speaking of the fusiform 

 stem of Iriartea ventricosa (vol. Ill p. LXXXV), writes that the swelling 

 is produced, not so much by an increase in thickness of the wood, but prin- 

 cipally by the more abundant and more lax parenchymatous tissue. While 

 greatly regretting that he had been unable to analyse the trunk of the said 

 palm, w^hen he had the opportunity of doing so, he reproduces a manuscript 

 note of Plumier on the swollen trunk of Euterpe f vinifera {Pseudophoenix 

 vinifera Becc). Of this palm Plumier says that at the point where the 

 upper portion of the inflated part begins to taper (corresponding to the 

 period in which the plant is about to produce fruit for the first time), the 

 tissues of the inflated part are soft and pulpy and contain a great quantity 

 of a very sweet juice, from which, by fermentation, a kind of wine is made. 

 The pith-like parenchymatous substance of the interior of the swelling must 

 be very soft and the jiiice it contains very abundant, as this latter is 

 obtained simply by squeezing the parenchymatous tissue between the hands, 

 after it has been reduced to a paste by repeated beatings with a pestle,* 



*Of Iriartea ventricosa Mart, writes, (v. Ill, page LXXXV) : Quaenam sit in ilia 

 parte tumida ligni compages, qui fibrarum ciecursus et quae ad materiem cellulosam ratio, 

 examinare, dum in palmae patria commorabar, quod valde doleo, neglexi, attamen mihi 

 persuadeo, in illo caudicis fuse materiem ligni nec frequentiorem, nec spissiorem esse, immo 

 parenchyma, fibris percursum, interiora laxius quam in reliquo caudice replere. 



And of the Euterpe? vinifera {Pseudo-phoenix) it is said (1. c. p. LXXXVI.) : Constat 

 vero haec singularis caudicis struma e substantia omogenea, medullosa, fructu Melonis 



