24 ON THE PROTEACEiE OF JUSSIEU.
all Proteaceae is a circumstance of the greatest importance in distinguishing the order from the most nearly related tribes ; and its constancy is more remarkable, as it is not accompanied by the usual position or even uniformity in the situation of the external umbilicus.
37] If Gaertner had not described the plumula of Protea argentea, I should not have hesitated to assert that it was inconspicuous in the whole order.
The number of cotyledons when more than two is a circumstance of little importance. In Persoonia, the only genus of the order in which a plurality of cotyledons has been observed, I am not even certain that their number is constant in those species in which this anomaly occurs.
In the following part of this essay it may be observed, that the genera into which I have subdivided the great African family Protea, are in most cases similar to those already proposed by Mr. Salisbury in the Paradisus Lon- dinensis : from that essay however they are certainly not derived, but before its publication were formed and sub- mitted to the judgment of Mr. Dryander, at whose sugges- tion they are now offered to the Society. That the results of an examination conducted by two observers wholly inde- pendent of each other, are so similar, will probably be con- sidered as some proof of their correctness.
As Mr. Salisbury's generic names have the unquestion- able right of priority of publication, I have in most cases adopted them, though I wish some of them had been differently constructed. But as I cannot accede to his application of the Linnean names Protea and Leucaden- dron, I shall here, that I may not disturb the following arrangement, assign my reasons for differing from him in this respect ; and as in so doing I am obliged to trace the progress of Linnaeus's knowledge of the family, I persuade myself that this will in some degree compensate for the otherwise unwarrantable length of the discussion.
The name Protea, which originated with Linnaeus, first occurs in the folio edition of his Systema Naturae pub- 38] lished in 1735 ; no generic characters are there given,
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