## 3 Results and Discussion
Despite these simplifications, a close inspection of Figure 2 suggests some interesting points to consider: If we calculate the ratios between the diameters of the various circles, i.e., A:B and B:C, we get the same value of 2.86, which allows A:C to be expressed as about n times C, where n is an integer and is equal to 9. This means that the pseudo-fractal feature that is apparent at first visual inspection of the SEM images can be confirmed as a numerical relationship based on this simple geometric observation. Figure 1: (**a**) SEM images at (\(53.54\times 66.33\)) \(\upmu\)m\({}^{2}\) of carbon nanopowders, obtained by pyrolysis of _Allium ccapa_, L., [41] and (**b**) false colors table from EDS total yield spectra; (**c**-**h**) separately false colors EDS images of C (red), Ca (light blue), K (green), O (dark blue), Mg (magenta), and S (yellow) and (**i**) the intensity of La\({}_{1}\), La\({}_{2}\) and K\(\alpha_{1}\), K\(\alpha_{2}\) emission lines, as a function of energy, of the elemental chemical impurities present in the C nanopowders. By increasing the magnification, as shown in Figure 2c, we can observe the petals of the individual nano-rose better, indicated, as a guide for the eyes, by the dashed pink circle. Each single petal (Figure 2d) has, on average, a lateral dimension of about 172 nm (pink arrow), with few larger or smaller petals. Furthermore, it seems that the individual nano-rose (see those within the yellow and red circles in Figure 2b) uniformly covers a hypothetical sphere, the largest, as a spherical shell of a smaller inner diameter. We can imagine that the two structures of a smaller diameter indicated in Figure 2a by yellow arrows are also composed, in the same way, by nano-roses, considering that they are shown to be jagged in their external lines, having a similar gleaning profile. This is an additional intriguing aspect since it would suggest that these pseudo-fractal structures present on the external surface of the sphere also occur inside its volume, assuming a 3D fractal similitude, where the single nano-rose may be considered as the building block. To identify the chemical composition of the nano-roses, we performed EDS microanalysis using the Bruker system. Figure 3a shows the SEM image that outlines the area where the EDS data were collected (3.8 K\(\times\), HV = 15 KV). Figure 3b-f display, respectively, the X-ray fluorescence maps for C, Ca, Mg, O, and Cu collected on the same area as in Figure 3a. Figure 2: (**a**) High-resolution SEM image, (58.56 \(\times\) 77.91) \(\upmu\)m\({}^{2}\), from C nanopowders supported on gold substrate at a magnification of 3.54 K\(\times\); (**b–d**) SEM images at a higher resolution of (17.92, 46.64, 169.32) K\(\times\) magnifications. Interestingly, we may observe from these elemental maps that the nano-roses are constituted of Cu, as shown in Figure 3f, and in particular by comparison of Figure 3e,f that are mainly composed of metallic Cu\({}^{0}\). This represents a very intriguing point, since to date, no structures similar to our nano-roses have been described, considering both the morphology of the crystallites and their composition. Typically, the nanostructures of copper reported in the literature, which were mainly obtained from a liquid phase  
Figure 3: (a) SEM image (3.8 K\(\times\), HV = 15 KV) that outlines the area of the EDS measurements reported in (**b–f**). The dashed yellow circle, located in the same position in all images, is superimposed as an eye guide to delimit the nano-roses’ structure. by the immersion of pure copper sheets, have been found to be systematically composed of oxidized copper, CuO [17; 18; 19; 20; 21; 22; 23; 24; 25], showing nanostructures in the form of flowers but completely dissimilar from those reported in this paper [25].