7. But let us return to the examination of the ingenious contrivances of creation. How many trees then arose, some to give us their fruits, others to roof our houses, others to build our ships, others to feed our fires! What a variety in the disposition of their several parts! And yet, how difficult is it to find the distinctive property of each of them, and to grasp the difference which separates them from other species. Some strike deep roots, others do not; some shoot straight up and have only one stem, others appear to love the earth and, from their root upwards, divide into several shoots. Those whose long branches stretch up afar into the air, have also deep roots which spread within a large circumference, a true foundation placed by nature to support the weight of the tree. What variety there is in bark! Some plants have smooth bark, others rough, some have only one layer, others several. What a marvellous thing! You may find in the youth and age of plants resemblances to those of man. Young and vigorous, their bark is distended; when they grow old, it is rough and wrinkled. Cut one, it sends forth new buds; the other remains henceforward sterile and as if struck with a mortal wound. But further, it has been observed that pines, cut down, or even submitted to the action of fire, are changed into a forest of oaks.  25  The phenomenon has been observed in later days, though Basil may be at fault in his account of the cause. When pines have been cleared away in North American forests young oaklings have sprung up. The acorn lay long hid, unable to contend against the pine, but, when once the ground was clear, it sprouted. This upgrowth of a new kind of tree had been accounted for partly by the burial of germs by jays, rooks, and some quadrupeds; partly by the theory of De Candolle and Liebig that roots expel certain substances which, though unfavourable to the vitality of the plant excreting them, are capable of supporting others. So, on the pine pressure being removed, the hidden seeds sprout in a kind of vegetable manure. cf. Sir Charles Lvell’s Travels in the United States and Rough’s Elements of Forestry, p. 19. We know besides that the industry of agriculturists remedies the natural defects of certain trees. Thus the sharp pomegranate and bitter almonds, if the trunk of the tree is pierced near the root to introduce into the middle of the pith a fat plug of pine, lose the acidity of their juice, and become delicious fruits.  26  Ambrose, Hexæm. iii. 13, writes: Amygdalis quoque hoc genere medicari feruntur agricolæ, ut ex amaris dulces fiant fructus, ut et terebrent ejus radicem arboris, et in medium inserant surculum ejus arboris quam Græci πεύχην, nos piceam dicimus: quo facto succi amaritudo deponitur. Let not the sinner then despair of himself, when he thinks, if agriculture can change the juices of plants, the efforts of the soul to arrive at virtue, can certainly triumph over all infirmities.

Now there is such a variety of fruits in fruit trees that it is beyond all expression; a variety not only in the fruits of trees of different families, but even in those of the same species, if it be true, as gardeners say, that the sex of a tree influences the character of its fruits. They distinguish male from female in palms; sometimes we see those which they call female lower their branches, as though with passionate desire, and invite the embraces of the male. Then, those who take care of these plants shake over these palms the fertilizing dust from the male palm-tree, the  psen as they call it: the tree appears to share the pleasures of enjoyment; then it raises its branches, and its foliage resumes its usual form. The same is said of the fig tree. Some plant wild fig trees near cultivated fig trees, and there are others who, to remedy the weakness of the productive fig tree of our gardens, attach to the branches unripe figs and so retain the fruit which had already begun to drop and to be lost. What lesson does nature here give us? That we must often borrow, even from those who are strangers to the faith, a certain vigour to show forth good works. If you see outside the Church, in pagan life, or in the midst of a pernicious heresy, the example of virtue and fidelity to moral laws, redouble your efforts to resemble the productive fig tree, who by the side of the wild fig tree, gains strength, prevents the fruit from being shed, and nourishes it with more care.

Ἀλλ' ἐπανέλθωμεν πρὸς τὴν ἔρευναν τῶν τεχνικῶν διατάξεων. Πόσα τότε γένη φυτῶν ἐπανέδραμε, τὰ μὲν ἔγκαρπα, τὰ δὲ ἐρέψιμα, ἄλλα πρὸς ναυπηγίαν ἐπιτήδεια, ἄλλα πρὸς καῦσιν; Ἐν τούτοις πάλιν ποικίλη μὲν ἐν ἑκάστῳ δένδρῳ ἡ τῶν μερῶν αὐτοῦ διακόσμησις, δυσέφικτος δὲ καὶ ἡ ἐξεύρεσις τῆς ἑκάστου ἰδιότητος, καὶ ἡ θεωρία τῆς πρὸς ἕκαστον τῶν ἑτερογενῶν διαφορᾶς. Πῶς τὰ μὲν αὐτῶν βαθύρριζα, τὰ δὲ ἀκρόρριζα: καὶ τὰ μὲν ὀρθοφυῆ καὶ μονοστέλεχα, τὰ δὲ χαμαίζηλα καὶ εὐθὺς ἀπὸ τῆς ῥίζης εἰς πολλὰς ἐκφύσεις διῃρημένα. Πῶς ὅσων μὲν οἱ κλάδοι προμήκεις ἐπὶ πολὺ τοῦ ἀέρος ἐκτεταμένοι, τούτων καὶ αἱ ῥίζαι βαθεῖαι, ἐπὶ πλεῖστον ἐν κύκλῳ διανεμόμεναι, οἷον θεμελίους τινὰς ἀναλογοῦντας τῷ βάρει τῶν ἄνωθεν ὑποτιθείσης τῆς φύσεως. Πόσαι τῶν φλοιῶν αἱ διαφοραί; Τὰ μὲν γὰρ λειόφλοια τῶν φυτῶν, τὰ δὲ ῥηξίφλοια: καὶ τὰ μὲν μονόλοπα αὐτῶν, τὰ δὲ πολύπτυχα. Ὃ δὲ θαυμαστὸν, ὅτι καὶ τῆς ἀνθρωπίνης νεότητος καὶ τοῦ γήρως εὕροις ἂν καὶ ἐν τοῖς φυτοῖς παραπλήσια τὰ συμπτώματα. Τοῖς μὲν γὰρ νέοις καὶ εὐθαλέσιν ὁ φλοιὸς περιτέταται: τοῖς δὲ γηράσκουσιν οἷον ῥυσοῦται καὶ ἐκτραχύνεται. Καὶ τὰ μὲν κοπέντα ἐπιβλαστάνει: τὰ δὲ μένει ἀδιάδοχα, ὥσπερ τινὰ θάνατον τὴν τομὴν ὑπομείναντα. Ἤδη δέ τινες τετηρήκασιν ἐκτεμνομένας ἢ καὶ ἐπικαιομένας τὰς πίτυς εἰς δρυμῶνας μεθίστασθαι. Τινὰ δὲ καὶ τὴν ἐκ φύσεως κακίαν ἐπιμελείαις γεωργῶν θεραπευόμενα ἔγνωμεν: οἷον τὰς ὀξείας ῥοιὰς, καὶ τῶν ἀμυγδαλῶν τὰς πικροτέρας, ὅταν διατρηθεῖσαι τὸ πρὸς τῇ ῥίζῃ στέλεχος σφῆνα πεύκης λιπαρὸν τῆς ἐντεριώνης μέσης διελαθέντα δέξωνται, εἰς εὐχρηστίαν μεταβάλλουσι τότε τοῦ χυμοῦ τὴν δυσχέρειαν. Μηδεὶς οὖν ἐν κακίᾳ διάγων, ἑαυτὸν ἀπογινωσκέτω, εἰδὼς ὅτι γεωργία μὲν τὰς τῶν φυτῶν ποιότητας μεταβάλλει, ἡ δὲ κατ' ἀρετὴν τῆς ψυχῆς ἐπιμέλεια, δυνατή ἐστι παντοδαπῶν ἀρρωστημάτων ἐπικρατῆσαι. Ἡ δὲ περὶ τὰς καρπογονίας διαφορὰ τῶν καρπίμων φυτῶν τοσαύτη, ὅσην οὐδ' ἂν ἐπελθεῖν τις δυνηθείη τῷ λόγῳ. Οὐ γὰρ μόνον ἐν τοῖς ἑτερογενέσιν αἱ διαφοραὶ τῶν καρπῶν, ἀλλ' ἤδη καὶ ἐν αὐτῷ τῷ εἴδει τοῦ δένδρου πολὺ τὸ διάφορον: ὅπουγε καὶ ἄλλος μὲν χαρακτὴρ τοῦ καρποῦ τῶν ἀρρένων, ἄλλος δὲ τῶν θηλειῶν, παρὰ τῶν φυτουργῶν διακέκριται, οἵ γε καὶ τοὺς φοίνικας εἰς ἄρρενας καὶ θηλείας διστῶσι. Καὶ ἴδοις ἄν ποτε τὴν παρ' αὐτῶν ὀνομαζομένην θήλειαν, καθιεῖσαν τοὺς κλάδους, οἷον ὀργῶσαν, καὶ τῆς συμπλοκῆς ἐφιεμένην τοῦ ἄρρενος, τοὺς δὲ θεραπευτὰς τῶν φυτῶν ἐμβάλλοντας τοῖς κλάδοις, οἷόν τινα σπέρματα τῶν ἀρρένων, τοὺς λεγομένους ψῆνας, καὶ οὕτως οἷον ἐν συναισθήσει τῆς ἀπολαύσεως γίνεσθαι καὶ ἀνορθοῦσθαι πάλιν τοὺς κλάδους, καὶ πρὸς τὸ οἰκεῖον σχῆμα τοῦ φυτοῦ τὴν κόμην ἀποκαθίστασθαι. Τὰ αὐτὰ δὲ ταῦτα καὶ περὶ τῶν συκῶν φασιν. Ὅθεν οἱ μὲν τὰς ἀγρίας συκᾶς παραφυτεύουσι ταῖς ἡμέροις: οἱ δὲ τοὺς ὀλύνθους ἐκδήσαντες, τῶν εὐκάρπων καὶ ἡμέρων συκῶν τὴν ἀτονίαν ἰῶνται, ῥέοντα ἤδη καὶ σκεδαννύμενον τὸν καρπὸν τοῖς ὀλύνθοις ἐπέχοντες. Τί σοι τὸ παρὰ τῆς φύσεως αἴνιγμα βούλεται; Ὅτι χρὴ πολλάκις ἡμᾶς καὶ παρὰ τῶν ἀλλοτρίων τῆς πίστεως, εὐτονίαν τινὰ προσλαμβάνειν, εἰς τὴν τῶν ἀγαθῶν ἔργων ἐπίδειξιν. Ἐὰν γὰρ ἴδῃς τὸν ἐν βίῳ ἐθνικῷ, ἢ ἀπό τινος αἱρέσεως ἐνδιαστρόφου τῆς Ἐκκλησίας ἀπεσχισμένον, βίου σώφρονος καὶ τῆς λοιπῆς κατὰ τὸ ἦθος εὐταξίας ἐπιμελούμενον, πλεῖον σεαυτοῦ τὸ σπουδαῖον ἐπίτεινον, ἵνα γένῃ παραπλήσιος τῇ καρποφόρῳ συκῇ, ἐκ τῆς τῶν ἀγρίων παρουσίας ἀθροιζούσῃ τὴν δύναμιν, καὶ τὴν μὲν ῥύσιν ἐπεχούσῃ, ἐπιμελέστερον δὲ τὸν καρπὸν ἐκτρεφούσῃ.