It likely refers to a cultivated or collected variation of the Philodendron mamei species, with the “cf” notation indicating that it may have some distinct characteristics or features compared to the typical or wild type of that species. The “cf” designation is often used in botanical terminology to denote a form or variant that is closely related to but potentially slightly different from the standard species.
This particular variation of Philodendron mamei might display unique attributes in terms of leaf shape, size, coloration, or growth habit compared to the typical species. To gain a deeper understanding of the specific characteristics and care requirements of this variation, it is advisable to consult with the source or collector who uses the “cf” designation, as they can provide detailed insights into this particular plant and how to best care for it.