454* VEGETABLE RESPIRATION. NoTE XXXVIEL

II. The organ ofreſpiration already ſpoken of belongs particularly to the ſhoots or buds, but there is another pulmonary ſyſtem, perhaps totally independentof the green foliage, which belongs to the frudtification only, 1 mean the corol or petals. In this there is an artery belonging to each petal, which conveys the vegetable blood to its extremities, expoſing it to the light and air under a deli- cate membrane covering the internal ſurface of the petal, where it often changes its colour, as 1s beautifully ſeen in ſome party-coloured poppies; though it 15 probable ſome of the irideſcent colours of flowers may be owing to the different degrees of tenuity of the exterior membrane of the leaf refracting the light like ſ0ap-bubbles, the vegeta- ble blood is then returned by correſpondent vegetable veins, exactly as in the green foliage; for the purpoſes of the important ſecretions of honey, wax, the finer eflential oll, and the prolific duſt of the anthers.

1. The vaſcular firucture of the corol as above deſcrib- ed, and which 1s viſible to the naked eye, and its expoſing the vegetable Juices to the air and light during the day, evince that it 15 a pulmonary organ.

2. As the glands which produce the prolific duſt of the anthers, the honey, wax, and frequently ſome odorifer- ous eſſential oil, are generally attached to the corol, and always fall off and periſh with it, it is evident that the blood is elaborated or oxygenated in this pulmonary ſyſ- tem for the purpoſe of theſe important ſecretions.

3. Many flowers, as the Colchicum, and Hamamelis, ariſe naked in autumn, no green leaves appearing till the

nſuing ſpring; and many others put forth their fowers