The want of any avowed principle of distinction, precludes all criticism of these natural orders of Lin nmus, as a regular system ; we can therefore only take a cursory view of them as they follow each other, with such indications of their characters as Giseke has recorded, or as we may ourselves be able to trace. A great part of the substance of the lectures, published by him, consists of remarks on the genera of each order, as to their mutual distinctions ; with numerous botanical and even economical matters, which do not all come within the compass of our present consideration. What we have to lay before the reader is not, in any manner, forestalled, by what he will find in the fourth volume of the ENCY.; CLOP/EDIA, above cited, which is taken from a diffe rent source.
Order 1. PALMAL " An entirely natural, ands very distinct order." This tribe of plants, by nature within the tropics, is considered by nicus as the original food of man ; still supplying the place of corn to the inhabitants of tropical coun tries. Palms are the most lofty of plants, and yev it is a matter of doubt whether they ought to be called trees or herbs. They do not form wood in concentric circles, year after year, like our trees, though they are extremely long-lived. The author of the sexual system was, as we have just mentioned in speaking of that system, but little acquainted at first with the structure of the flowers of palms, or the number of their stamens or pistils. His pr:de cessors in the establishment of genera of plants, Tournefort and Plumier, had published little or no thing illustrative of this tribe. He had'himself seen no more than dwelt or four species in fructification, nor had he any other resource, in founding generk than the plates of the Hortus Malabericus, (excellent indeed, but not delineated with any particular view of this kind,) and the less complete representations of Rumphius. The growth of these plants is quite simple. Each terminates in a bud, of a large size, called the heart, or by voyagers in general the cab bage, of the palm. When this is cut off, the tree dies, though the growth of many centuries. This bud has a gradual and nearly continual vegetation, unfolding its leaves, Which Linnieus rather incorrect ly terms fronds, one after another in succession, not all at any partieular season. The bud therefore is perennial, not, as in our trees, annual, nor can it, for this reason, be renewed. Fresh buds, in time be coming trees, are furnished from the generally creeping, perennial, and deeply descending roots. What have commonly been denominated the branch es of Palms, Linnaeus very properly declined calling so, because they never increase by producing lesser branches. He objected to calling them leaves, " be cause they are each attended by no separate annual bud, neither have they the texture of ordinary leaves, nor do they wither and fall off at any particular sea son." He adopted the term frond, which he always used when he could not decide whether the part in question were a branch, leaf, or stem. We cannot but think these are truly leaves, though it must be confessed they differ from the generality of such, in being destitute of any line of separation' by which they are capable of falling, or being thrown off, from the stem. In this they agree with the foliage of
Maxi and Jungermannia ; there being a perfect continuity of substance throughout. The hardened torn fibres, or rather vessels, which remain on the stems of palms, where the leaves have once been, are precisely the same as what occur in various mosses; and something similar may be observed in many lilia ceous plants and their allies, which approach to the nature of palms.
In describing the fructification of this order, Lin naeus considered as belonging thereto, what we should presume to be rather the inflorescence. Hence the great branching fiowerstalk retains, in a technical sense, the name of spadix, derived from the ancients ; and its ample containing sheath is de , nominated a spatha. The latter is reckoned a kind • of calyx, as the former a sort of branched common receptacle. Linnaeus strengthens his terminology in this case, by tracing an analogy between the spatha of palms, and the glume of grasses. We doubt whether any such particular analogy exists. Nei ther does his other comparison, of the part in ques _ tioti to the sheath of a Narcissus and its allies, at all, as far as we can judge, elucidate or confirm his principle. He surely swerves in these instances, as well as in his generic distinctions of the umbellife rous plants, from the correctness of an axiom, on which botany as a philosophical science depends, that generic characters, and much more those of classes and orders, should be exclusively,derived from.the parts of fructification. Surely a very slight consideration of the flowers and fruits of the Palma, is we have become acquainted with them since the time of Linnaeus, will abundantly satisfy any person, that they afford clear characters, on which to found a sufficient number of distinct and very natural ge 'nets. Even that author, in the lectures before us, records that some genera have a three-leaved calyx, others none at all ; some have a corolla of three, others one of six, petals ; most have six, stamens, some three, others nine, while the Nipa of Thunberg has only one. The germens are three in some, soli tary in others, and the stye and stigma are subject to like diversity in different genera. The fruit is in some, as the PAcenix dactylifera, or Date, a single dnipa, in others composed of three ; in some, like the Cocoa, a nut with a coriaceous coat. The seeds are mostly solitary, but in several instances two or three in each fruit. Hence, while the fructification affords sufficient materials for discriminating genera, Linnaeus observes that no common character, exclu sively descriptive of the whole order, can be found ed upon it. The reader will find the essential cha racters of his genera in our Vol. IV. 288. His Za mia, concerning which he avowed considerable doubts, chiefly because it wanted a spatha, is now, by com mon consent among botanists, removed either to the Ferns, or to an intermediate order between them and the Palms, to which also Cyeas belongs. The tech nical characters which have induced this alteration, are confirmed by circumstances attending the habit and qualities of these genera.