De Magnetica [...] Plantarum p. 641

follows the sun even when the sky is clouded over, that it even twists the stalk, or stem, itself. The leaves of Acacia, with which we are well supplied here in the Roman College, so love the sun that as soon as it has risen they gradually unfold their frilly character toward the south, as if displaying their elegant appearance for all to see; but at sunset it contracts those same leaves so that you might say they were not leaves but juniper needles. But it is a surprising thing that Theophrastus (bk.4, ch. 10) says about the Lotus: It grows its fruits in a head, in the way a bean does; the flower is white, close to lilies in the narrowness of the petals; many and dense, they emerge freely; at sunset they close up and cover the head, and at sunrise they open and rise up above the water, and they do that until the head is completed and the flowers fall away: the size of the head is as great as a very large poppy, except that in these the fruit is held more plentifully and is not dissimilar to millet. In the Euphrates they say that the head and the flowers sink, and descend until the middle of the night, disappearing to such a depth that you could not reach your hand down and take hold of them; then at dawn they come back up, and more so toward the day, and as the sun rises they are already emerging from the water and revealing their flower, after which it continues to rise up so that it is clearly high out of the water. Thus far Theophrastus. Having enquired into all these things with particular diligence from those who have toured those parts, I have found them to be true. So there is a certain power within plants by which they imitate not only the daily motion of the sun but also its proper, or annual, motion. For there is no lack of trees and plants which put on a continous increase of leaves from the first stage of germination until the sun's solstice, and grow continually with the sun: but when the sun turns back they too turn back, and decrease until the equinox, until deprived of the presence of the sun as it departs into the southern hemisphere, they wither as if grieving. A sort of beginning of this motion is seen in many other plants, but most powerfully in those trees whose leaves are green on one side but whitish on the other, like those borne by firs and a certain sort of willow. Relevant here is what Francisco Perez, Procurator for the Philippine Islands in the affairs of our Society, reported in previous years about a certain quite remarkable Heliotropium. On Quilola Island, on Mindanao and on other neighbouring islands he says there is a shrub whose flower so constantly looks toward the sun that it never deviates from it by a finger's breadth. For when the sun first approaches the equator and is positioned at the point of rising, the flower, as if woken from a deep sleep and sensing the presence of her bridegroom,