ON THE PROTEACE.E OF JUSSIEU. 19
The figure of the pollen has been attended to by a few theoretical, but by hardly any practical botanists ; yet I am inclined to think, not only from its consideration in this family, but in many others, that it may be consulted with advantage in fixing our notions of the limits of genera : and though its minuteness may perhaps always exclude it from a place in generic characters, yet it well deserves, to use the words of Linnaeus when speaking of habit, to be "occulte consulendus."
Its usual figure in the order is triangular with secreting angles, a beautiful contrivance for insuring impregnation in a tribe, in which, from the very scanty, or in many cases apparent want of secretion by the stigma, it must other- wise have been very uncertain ; for by this form and secre- tion, as well as by the singular ceconomy of the calyx, it remains so long in contact with the stigma, as probably to compensate for the somewhat defective structure of that organ.
From this figure the principal deviation is in the exten- sive genera Banksia and Josephia, in all of which it is elliptical or oblong, and either straight or bent into a semi- lunar form ; and in Franklandia and Aulaoc, where it is spherical. The only remaining exception with which I am acquainted is the original Embothrium of Forster, his E. coccineum, in which, as in Banksia, it is oblong ; a circum- stance that, together with the more important character of a regular club-shaped stigma, and some other differences, has determined me to separate it from all the other species of Embothrium, except E. lanceolatum of Flora Peruviana, whose pollen however remains to be examined.
The external modifications of the ovarium must be very cautiously used in the generic characters of this family j [32 even its being sessile or pedicellated is not always of suffi- cient importance, though I think Mr. Salisbury has done well in introducing it into his characters of Serruria and Spatatta, in both which genera I had overlooked it before the publication of his Essay.
Its internal structure, which ought always to be ascer- tained, will be found of the greatest importance in most
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