O. F. Cook

“ In Thrinax praeceps the leaf-bases split below in the median line and remain long attached to the trunk. This adaptation is not confined to the old leaves but appears while the leaves are still very young, or as soon as they begin to be expanded by the pressure of those above them. In the tall species such pressure separates the fibers of the opposite side of the cylinder. The short species has the outside of the leaf-bases densely tomentose, and the tomentum is especially abundant along the edges of the split midrib of the young leaf. ”

“ The native palms of Puerto Rico may thus be said to represent a distinctly Antillean or Caribbean series, only Acrocomia and Bactris being known to have a wider distribution.
The list of introduced palms, consisting of the date, the cocoanut, and the betel, might have been somewhat increased by canvassing ornamental gardens, but it does not appear that any other introduced species has been put to any useful purpose or has escaped into general culture, certainly a remarkable fact when we consider the number and importance of the economic palms of other tropical countries. ”

“ Possibly no ecological differences exist among the Thrinax-like palms of other regions, but in Puerto Rico there are, as shown in the discussion of the following genus, two well-defined types, one of which varies the ordinary short columnar habit by the possession of a tall slender and flexible trunk which doubtless enables it to compete in a measure with the rapid growth of the surrounding vegetation, and which is also obviously adapted for withstanding the force of the strong winds encountered in the exposed places apparently preferred by palms of this species. ”

“ In Jamaica there seem to be at least two species of Acrocomia, the larger of which is called the “great macaw” palm, and is described as having a fusiform trunk as thick as a man’s body. What is presumably the same species occurs in Cuba as shown by a photograph from the vicinity of La Gloria on the north coast. The greatest diameter of the trunk is three or four times the thickness near the base. In Puerto Rico no trees approximating these proportions were observed, the greatest amount of swelling probably not reaching twice the diameter below. ”

“ The heart of the bundle of leaf-bases, about two feet long and three inches thick is eaten as a salad, with oil and vinegar. It is also stated that the deciduous boat-shaped spathes serve as reservoirs of rain-water which is long retained in the cool shade cast by the trees. Birds and beasts, and human natives as well, are said to be dependent at times upon the liquid thus stored, since in the regions where the palm grows there are at times no other means of procuring water. The forests of the high mountain chain of Buena Vista in the province of Caracas are the native home of the species. ”

“ The tall, slender trunk and other differences between this genus and Thrinax are probably to be interpreted as ecological adaptations necessary to enable the present palm to compete with the vegetation which often surrounds its base, and to withstand the winds to which it is commonly exposed. The species of Thrinax and other allied genera, as far as known, have the trunk rigid and columnar, or even enlarged from the base upwards. When growing solitary and exposed they seldom, if ever, attain half the height of Thrincoma. ”

“ If the palms under observation near Ponce belonged, as was believed, all to one species, it is not only true that the individual Thrinax passes all the stages from the narrow and grass-like, almost completely separated segments of the very young plant, to the more than half united leaf of the large tree, but it also appears to be true that under unfavorable conditions a Thrinax may not be able to attain to full maturity of size and form but may at the same time produce flowers and seeds. ”

“ It is perhaps too soon to assert that there is only one species of the present genus in Puerto Rico. The trees certainly differ considerably in size though not more than the cocoanut and others. There is also a noticeable difference in the abundance of spines. Such apparent variability may, however, be due to age, the older trees tending to become less densely beset with the brittle black spines which are often conspicuous on young specimens. ”

“ A compensating advantage may be drawn, however, from the definite and often very limited geographical distribution of the species of palms. Thus, although Puerto Rico is a relatively small island, several of the indigenous palms have apparently ranged in nature over but a small part of it, and a locality definitely indicated would often go further toward establishing the identity of a species than much of the descriptive matter prepared for this purpose. ”

“ The narrow petiole of the tall species affords greater flexibility in the lateral plane while strength has been secured by the greater thickness. On the other hand the thinness of the base of the petiole of Thrincoma reduces resistance by permitting the petiole to be twisted when the leaf is opposed to the wind or blown laterally, thus avoiding the strain which would come upon the more rigid base of the petiole in Thrinax. ”

“ The first species is Oreodoxa acuminata, referred by recent authors to Euterpe but probably constituting a distinct genus. The trunk is erect, cylindrical, very smooth, and attains a height of from 15 to 18 metres; the “root” throws out suckers at the base of the trunk. The fronds are pinnate, with opposite or alternate, very long, ensiform, acuminate pinnae, replicate at base. The strongly convolute young leaves form a green apex for the trunk, five feet high. Spathes cinereous, folded in at the base of the leaf-sheaths at the top of the trunk, univalvate, deciduous ”

“ The leaves of Sabal are adapted for standing erect and avoid resistance to the wind by being split down the middle. The leaves of Inodes which are held horizontal from an erect axis have attained the unique adaptation of a decurved midrib which braces the sloping sides of the leaf and effectively prevents the breaking above the ligule common in some of the species of Thrinax. ”

“ Three fruits develop from one flower only exceptionally. The trunk is of more than medium height, and the inflorescence is in reality infrafoliar, for although the dead leaf-bases and midribs of the leaves are persistent and support the long inflorescence, this condition is not comparable to that of the cocoid and other really interfoliar inflorescences.
Aeria attenuata sp. nov. Plate 45. The tallest of Puerto Rico palms, probably attaining 30 metres and upward. The trunk is supported on a mass of coarse roots with spine-like projecting rootlets arranged in whorls. ”

“ In Thrinax Ponceana the leaves of well grown trees have the middle divisions united to about the middle; the smaller the leaves, the more deeply they are divided. A further correlation with size is that of the “fullness” of the leaf. The basal sinus is not closed by the overlapping of the lateral divisions as in some species, but the area is too great for a plane circle and there are one or more folds, more numerous and deeper in large leaves. ”

“ This species apparently exists in much larger quantities than any other yet known from Puerto Rico, being the predominant plant on several square miles of territory along the range of dry limestone hills which skirt the southern coast of the island, to the west of Ponce. Many of the palms are scattered among the taller shrubs and trees wherever there is sufficient soil and water to permit these to grow and yet not enough to give them exclusive possession, 537but on many of the drier and more sterile higher slopes the advantage is with the palms. ”

“ But the vast majority of royal palms now in existence in Puerto Rico stand on land which has been cultivated at one time or another, and where the palms were able to secure a foothold before the competition of other plants became too strong.
The discovery of root tubercles on a young plant of this species has been noted in the introductory statement. These tubercles though small in size are very numerous upon the smaller roots. In shape they are mostly oval and symmetrical. The larger are about 2 mm. ”

“ The second of the original species of Oreodoxa is now referred to the genus Catoblastus. It is a somewhat smaller tree from 12 to 15 metres high, with a generally similar habit, and is also stoloniferous, but the pinnae are broad, cuneiform and praemorse, or irregularly truncate as in the species generally referred to Martinezia. The drupaceous fruit is grayish and the pulp is only slightly succulent; seed the size of a pigeon’s egg, its exterior brown, marbled with numerous veins. ”

“ In both genera the nuts are unsymmetrical, the side which has the largest foramen being distinctly larger than the others and in Curima the irregularly pitted sculpture is coarser.
ACROCOMIA Martius, Hist. Nat. Palm. 2: 66 A genus of palms distributed through tropical America from Mexico to Cuba and Paraguay. All the species are of stocky, compact growth, with a dense crown of numerous leaves. The trunk and the leaf-stalks are usually armed with strong, sharp spines, sometimes several inches long. ”

“ Key to the Genera of Sabalaceae Leaves depressed in the middle, with a distinct decurved midrib; a slender fiber rising from each of the notches which separate the leaf segments.
Inodes. Leaves flat, midrib rudimentary; segment without alternating fibers.
Leaves chartaceous, naked on both sides when mature, the veinules unequal; fruits nearly sessile; seeds smooth, albumen solid except for a deep basal cavity.
Thrinax. Leaves tough and coriaceous, the lower surface silvery with a persistent, closely appressed pubescence; veinules equal; fruits distinctly pedicellate ”

“ Martius, and Jacquin’s older name Areca oleracea stands in the same relation to Euterpe edulis Martius, thus rendering Euterpe oleracea Martius a specific homonym. Subsequently Martius claims the genus Euterpe for himself and expresses doubt whether it is the same as that named by Gaertner, while Drude in Engler and Prantl’s Natürlichen Pflanzenfamilien says “Euterpe Mart. (nicht Gaertn.) .” Martius also admits that the West Indian Areca oleracea Jacquin is distinct from the Brazilian species of Euterpe, and redescribes it under the name Oreodoxa oleracea. ”

“ The enlargement at the ligule is abrupt. The base widens gradually to about 2 cm. but is much thinner than in the short species. In the upper part of the petiole the reverse is true, the cross section of the leaf-stalk of the Thrincoma being almost diamond-shape, while that of Thrinax is merely lenticular.
4. These differences of proportion of ligule and stalk are obviously correlated with the different habits of the two species. The shorter and more robust trunk of the one enables it to withstand the strain of the relatively limited exposure to the wind. ”

“ The normal segments are split at the apex to the distance of from 2 to 8 cm. and the tips are usually markedly divaricate, owing to the fact that the young leaves of this species suffer two impressions from the bases of older leaves, one near the middle, the other near the end. The pressure causes the curvature of the unopened leaves, which in turn causes them to split apart when the leaf expands. ”

“ Originally the royal palm and the corozo were probably confined to the more rugged slopes of the lower limestone hills where they both still retain a foothold in places where the natural growth seems never to have been cleared away. ”

“ As shown by the rimose bark this species affords a rather extreme instance of the gradual enlargement of the trunk at a distance from the growing point. Numerous leaf-bases remain attached to the trunk in the greenhouse as they would not do in nature, since they are torn loose except for a few fibers at the extreme sides. ”

“ For the present, at least, the geographical idea should be kept uppermost in systematic studies of the palms, since it is generally much easier and far more logical to extend the limits of supposed distribution and unite supposed species, than to cope with the confusion caused by the miscellaneous reporting of species far outside their natural ranges. ”

“ In the narrow chinks and crevices of the bare rocks were very small, stunted trees, obviously of great age, while but a few feet distant a deeper fissure might hold vegetable débris and moisture sufficient to nourish vigorous specimens several times the size of their less fortunate companions. The stunted trees retain in proportion to their size, but apparently with little reference to their age, the small deeply divided leaves of young plants and have short few-branched inflorescences, another difference of supposed systematic importance. ”

“ From the popular standpoint another serious inconvenience of the systematic literature of palms arises from the fact that it is based so largely on floral characters that even the botanical traveler might need to wait months for the blossoms and then climb the trees or cut them down before being able to secure a clue to botanical names or relationships. ”

“ It might then be argued by some that Miller’s species, Palma altissima constituted a segregate from Jacquin’s oleracea and that the latter name is available for the Acrista of Martinique, whether identical or not with that of Puerto Rico. But with a possible doubt between the Acrista and the Roystonea there can scarcely be a justification for the use of the same name for a third South American species or a fourth West Indian. ”

“ Key to the Genera of Bactridinae Trunk small, cespitose; leaves separated by long internodes; foramina of seeds apical.
Bactris. Trunk medium or large, solitary; leaves crowded together at the summit; foramina peripheral.
Trunk slender; leaf-divisions broad, praemorse-truncate; pistillate and staminate flowers intermixed on the inflorescence; exocarp fleshy.
Curima. Trunk robust; leaf-divisions narrow, sharp-pointed; pistillate flowers below and separate from the staminate; exocarp fibrous.
Acrocomia. BACTRIS Jacquin, Stirp. Am. 279. pl. 271. ”