NO. 7 A NEW PALM FROM COCOS ISLAND — COOK 25 



of gradual suppression. In retaining the large bracts, Plcctis may be 

 considered as less specialized, and also in having the two large basal 

 spathes nearly equal, the first somewhat larger than the second, the 

 usual relation being that the first or outer spathe is much shorter, with 

 the inner spathe emerging at a relatively early stage of development, 

 and becoming much firmer in texture than the outer spathe. 



Each of the flower clusters is subtended by a bract, as though rep- 

 resenting a shortened branch of a primitive compound inflorescence, 

 and four, other bracts are represented in each flower cluster, one on 

 each side of the female flower, usually overlapping at the ends, form- 

 ing an upright persistent collar around the base of the flower. Outside 

 the collar bracts are two others, much smaller, each subtending a male 

 flower, these male bracts decurrent between the collar bracts and the 

 upward extensions of the basal bract, at the sides of the female flower. 

 The basal bract is nearly as prominent as the collar bracts and often 

 distinctly apiculate. The collar bracts are angled or broadly rounded, 

 somewhat carinate at the back, and thickened with parallel fibro- 

 vascular ribs like the basal bract and the calyx, though less so than 

 in Rooscvcltia. Surface of basal bracts and also of collar bracts cov- 

 ered with short tomentum like that of the branches. This functional 

 involucre in Plcctis and related genera is in contrast with Acrista and 

 Orcodoxa, which have the bracts minute and rudimentary, buried 

 under the flowers in the depressions of the thickened branches. 



Small off-shoots are formed on young palms, as shown in the pho- 

 tograph, though under forest conditions only one trunk is developed 

 from a cluster of roots. On a cut or injured trunk another off-shoot 

 may develop, as observed in several cases where roads or temporary 

 clearings had been made through forest areas. 



The fact that all the young palms are much more slender than the 

 mature individuals leaves no doubt that a gradual thickening of the 

 trunk takes place during development, although the surface is nearly 

 smooth and evidences of enlargement were not obvious on the largest 

 palms, that may have attained the full diameter. On palms of medium 

 size, a more rapid thickening may take place, and longitudinal fissures 

 of the outside layer were in evidence, although the surface is kept 

 nearly even by the furrows filling with a new growth of brownish, 

 barklike, corky material. Also it was noticed that a rather soft outer 

 layer could be distinguished, with fibers much smaller than those of 

 the harder "wood" underneath. By a gradual addition of fibers on 

 the outside, fine at first and gradually thickened, a form of exogenous 

 growth seems possible. 



