**2. Materials and Methods**

This article is a review of the main scientific articles published regarding the study of the different stages required for in vitro micropropagation of *Syngonium podophyllum* Schott. cv. 'White Butterfly' by our laboratory, and with reference to the current literature, in our attempt to improve our understanding of de novo shoot formation from callus.

This article is structured in three parts. The first part is dedicated to discussing the main principles followed for setting an industrial micropropagation protocol, along with underlying opportunities and obstacles based on our experience.

In the second part, we further discuss the materials and methods applied for developing an industrial micropropagation protocol, as described in three published articles [31–33] as well as in a doctoral thesis [34]. All three scientific articles were published in the English language—two of them in Romanian journals and one in a journal from the United States. The thesis was published in the Romanian language. All stages—including the starting plant material, sterilization, meristem culture, initiation, micropropagation, and acclimation—are discussed with respect to the existing scientific knowledge on the species. Wounding stress, callus formation, and histological studies of calli are discussed as relevant in order to further contribute to our understanding of the process of de novo shoot formation in syngonium.

In our search strategy implemented in Google Scholar, we included all scientific articles studying the species *Syngonium podophyllum* whose full text was freely available in the English language [35]. In this strategy, the year 1976 was set as the starting point, when the first published article was recorded [22]. There are also some valuable closed-access articles available online, which are mentioned in this paper as citations in the required contexts. However, in choosing the most relevant scientific articles for discussion in this article, the focus was on the following keywords: callus development, callus histology, and de novo shoot formation.

The scientific names of the plant species were all validated against recognized plant taxonomic databases [36–38].

#### **3. Results and Discussion**
