Although there is a peculiarity of habit that enables one soon to detect an orchidaceous plant even when not in flower, yet they vary greatly in size and aspect. Some of the small creeping species are hardly larger than mosses, while the large Grammatophyllums of Borneo, which grow in the forks of trees, form a mass of leafy stems ten feet long, and some of the terrestrial species--as the American Sobralias--grow erect to an equal height. The fleshy aerial roots of most species give them a very peculiar aspect, as they often grow to a great length in the open air, spread over the surface of rocks, or attach themselves loosely to the bark of trees, extracting nourishment from the rain and from the aqueous vapour of the atmosphere. Yet notwithstanding the abundance and variety of orchids in the equatorial forests they seldom produce much effect by their flowers. This is due partly to the very large proportion of the species having quite inconspicuous flowers; and partly to the fact that the flowering season for each kind lasts but a few weeks, while different species flower almost every month in the year. It is also due to the manner of growth of orchids, generally in single plants or clumps which are seldom large or conspicuous as compared with the great mass of vegetation around them. It is only at long intervals that the traveller meets with anything which recalls the splendour of our orchid-houses and flower-shows. The slender-stalked golden Oncidiums of the flooded forests of the Upper Amazon; the grand Cattleyas of the drier forests; the Cœlogynes of the swamps, and the remarkable _Vanda lowii_ of the hill forests of Borneo, are the chief examples of orchid-beauty that have impressed themselves on the memory of the present writer during twelve years’ wandering in tropical forests. The last-named plant is unique among orchids, its comparatively small cluster of leaves sending out numerous flower-stems, which hang down like cords to a length of eight feet, and are covered with numbers of large star-like crimson-spotted flowers.