On the relative position of the divisions of stigma and parietal placentae in the compound ovarium of plants / by Robert Brown.

  • Brown, Robert, 1773-1858.
Date:
[1840]
Catalogue details

Licence: Public Domain Mark

Credit: On the relative position of the divisions of stigma and parietal placentae in the compound ovarium of plants / by Robert Brown. 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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    Position of the Stigma and Placenta; in Plants. 35 having a cavity of about an inch at the back of the slielves (two cross bars might prevent the plant-holding papers from being pushed too far back) with a lid at the top, and sliding in one or more frames supporting Welsh Plane well dosed with the chloride and dried; gun-wadding prepared might perhaps do as well, but I have not at present tried either material. A servant might occasionally take out, dry, and replace the slides M'ithout having access to the plants. One unconnected remark and I have finished: my vasculum is provided with a canvass Hning, which I take care to have well-wetted in warm weather, to supply much of that moisture that would other- wise diffuse into the air from the contained plants alone. It is further provided with a covering of canvass to be used only in hot sunshine when it is wetted to keep the box cool by evaporation from its surface. VVoodloes, near Warwick, November 1842. XI.— On the relative position of the Divisions of Stigma and Parietal Placenta in the Compound Ovarium of Plants. By Robert Brown, F.R. & L.S.* To estimate correctly the importance of the relation between the divisions of the Stigma and the parietal placentae of the compound ovarium, namely, whether when agreeing in num- ber they are placed opposite to or alternate with each other, it is necessary to take into consideration the theoretical view which appears the most probable of the origin or formation of a simple ovarium, and that of the stigma belonging to it, as well as the various kinds and degrees of confluence l)y which the real nature of both organs, but especially the latter, is so often obscured. It is at present, I believe, universally agreed to consider a polyspermous legumen as that state of the simple ovarium, which best exemplifies the hypothetical view of the formation of this organ generally adopted; namely, that it consists of the modification of a leaf folded inwards and united by its mar- gins, w^hich in most cases are the only parts of the organ pro- ducing ovula; or, at least, where this power of production is not absolutely confined to the margins, it generally commences with or includes them. The exceptions to the structure as here stated are of two kinds:— First. Where the whole internal surface of the carpel is * This article, which is referred to at p. 255 of No. 65, is extracted from Mr. Urowii a account of Cyrtantlna', given in tlie second part of Dr. Hors- field s ; I lant£e Javanica; Rariores,' ]nibiished in ) 810. Separate copies of this article were distributed in Decernbt-r, 1,';39 D 2