Manual of Botany (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1851 Excerpt: ... following tables show some of their results: --No. of Colour. Gpecies. Odoriferous. Agreeable. Disagreeable. Thus, of the plants examined, those having white flowers presented the larger proportion of odoriferous species. The orange and brown coloured flowers often gave a disagreeable odour. In examining numerous species from various natural orders, they found that out of 100 species of--Nymphfeacefe 22 were odoriferous. Rosacea; 13 Primnlacea? 12 Boraginacea; 6 Convolvulacea: Kanunculacece. 4 Papaveracea; 2 Campanulacea? 1 6.--DISEASES OF PLAMTS. 689. Great obscurity attends this department of botany, and much remains to be done ere a system of vegetable nosology (-oVoc, disease) can be completed. It is, however, of great importance, whether we regard its bearing on the productions of the garden or the field. Some have divided the diseases of plants into general, or those.affecting the whole plant, and local, or those affecting a part only. A better arrangement seems to be founded on their apparent causes, and in this way they have been divided by Lankester into four groups. 1. Diseases produced by changes in the external conditions of life; as by redundancy or deficiency of the ingredients of the soil, of light, heat, air, and moisture. 2. Diseases produced by poisonous agents, as by injurious gases, or miasmata in the atmosphere, or poisonous matter in the soil. 3. Diseases arising from the growth of parasitic plants, as Fungi, Dodder, &c. 4. Diseases arising from mechanical injuries, as wounds and attacks of insects. 690. Plants are often rendered liable to the attacks of disease by the state of their growth. Thus, cultivated plants, especially such as become succulent by the increase of cellular tissue, appear to be more predisposed to certain...