Introduction to cryptogamic botany / by M.J. Berkeley.

Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: Introduction to cryptogamic botany / by M.J. Berkeley. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    9 INTRODUCTION TO CRYPTOOAMIC IJOTANY. with Lilium* Attentive study will soon prove the two grand divisions above-named of Exogens and Endogens to be founded in nature, as far as any divisions can be shown to be so, by their mode of germination, the law of increase in their stems, and the venation of their leaves; and so in the minor groups, though there will be many a preconception to overthrow, still structure will as before confirm the indications of outward form, except, as said above, where such indications are mere matters of external resemblance, apart from every essential character. 2. The eye, however, will have already distinguished a third grand class,-f- more distinctly indicated perhaps even than the other two, though composed of parts still more widely differing from each other. It will have seen the rocks and trees covered with pigmy forms of vegetation, often displaying nothing like a leaf, or the peculiar green tint of the vegetable world; or if something approaching to a stem and leafy appendages be present, so cramped, attenuated and filmy, at once so easily dried up by heat, and capable of being restored by moisture, as to present something at once distinguishable from ordinary vegetation. The waters, whether fresh or salt, meanwhile teem with other vegetable organisms, distinguishable at once from the mere aquatic Pheenogams amongst which they grow, and * After a patient examination of germinating plants, and an atten- tive consideration of tlie whole question, I cannot but subscribe to the view which considers Nymphcea as a true Exogen, notwithstanding some anomalies of structure in the common stem, and the peculiarities of the seed. Nor, again, can I subscribe to that view which would place Nelunibium and Nymphcea in diflFerent divisions, though, if that were correct, no better example could be adduced in illustration of the text. t I cannot consider Dictyogens (much less Ehizogeus and Gymno- gens) as a class of the same importance with Endogens and Exogens. They are so clearly Endogenous, notwithstanding the peculiarities of the venation or much more of the structure of the stem, which may be easily studied by English botanists in Tamus, that, unless every anomaly is to be considered as overthrowing a natural division, we must either be content to leave them in company with their allies, or give up the attempt of natural arrangement altogether.