The interstitial or cementing substances in the Elgin sandstones.

  • Mackie, William.
Date:
[1901]
Catalogue details

Licence: In copyright

Credit: The interstitial or cementing substances in the Elgin sandstones. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    an average, and the width would vary from four to eight inches at the widest points. The fronds are usually yellowish green, having a dull ap- pearance and paler in aspect than any British fern in the North with one exception, which is similar in colour. The texture is rather thin. But the most remarkable part of this plant is the stalkless glands with which the fronds are clothed on the under side. They are small in size, and are generally present where the fern can develop in any sort of Shape. They have been variously described, one definition being resinous or glandular dots on the under side of the fronds. The latter, we may here notice, commence, but in very small form, at the very bottom of the stem, and the glands practically commence with them. It is in these glandular dots that the scent exists, which is compared to the strong smell of lemons, and may be felt at any time where the fern is growing, varying more or less with the nature of the weather, probably best felt in dew or moderate sunshine, vanishing in some degree with extreme drought, to appear strongly with a refreshing shower. This all re- fers to the fern without touching it; but, when the fern is bruised, the scent can be felt on the hands at all stages and in all weathers, from the emerging of the plant in spring, until the fronds wither away in the succeeding winter, for a shrivelled up frond when bruised between the fingers will give out smell. It is rather late in commencing to unfold in the spring, and resembles a ball bristling with recurved points. It grows rather rapidly, and, being weak in durability, is as easily destroyed with cold autumnal winds or early frosts as any of our ferns, or late spring frosts leave their mark upon young plants of this one as severely as on any represented here. It is, however, a good drought resister, compared with its dura- bility under previously mentioned conditions. As regards the venation of the fern, a wavy vein goes from the mid vein into each lobe of the pinnae; from it again branch venules and at times veinlets in the larger lobes, the latter being branches off the former. We find both on the venules and veinlets nearest to the vein what is called the receptacle, that is, an enlargement where the sori and spores or seeds are situated. As