The Collections of this Department consist of two portions, the one open to the public and consisting of specimens suitable for exhibition, and mainly intended to illustrate the various groups of the Vegetable Kingdom and the broad facts on which the natural system of the classification of plants is based; the other set apart for the use of persons engaged in the detailed scientific study of plants. On the landing outside the gallery is a series of tree-sections representing some common British-grown trees, with sections and bark of the Cork-Oak (_Quercus suber_), and large sections of the White Fir and Douglas Pine from British Columbia. The Douglas Pine was cut down in 1885 when 533 years old; its age is indicated by the annual rings seen in transverse section of the wood, and a record of events has been painted on the surface. A collection of plant-abnormalities is also shown. [Sidenote: System of Classification.] The system of classification followed in the exhibition-cases in the public gallery is a modification of one widely used on the Continent and in America. In the first bay on the left-hand side an attempt has been made to illustrate, by means of books dealing with the subject, the history and development of modern systems of classification. There is a _Guide_[26] to this exhibition. The series of specimens (starting on the north, or left-hand, side of the gallery) begins with the simpler orders of Dicotyledonous Seed-plants, those in which petals are wanting in the flower or if present are free from each other, and passes on to the less simple orders with united petals. The orders are represented by dried or otherwise prepared specimens of the plants themselves, drawings, fruits, and prepared sections of the woods. Diagrams are employed to indicate the characters in the flowers on which the grouping is based. The use of the same colour for corresponding structures throughout the diagrams readily conveys to the eye the points of agreement or difference on which the classification rests. The geological history of each natural order is indicated on a table of strata, and its present distribution on the surface of the earth given on a small map of the world. Descriptive labels afford particular information respecting each specimen.