A group of scientists from the Malaysian Agricultural Research and Development Institute have documented the anatomy of the kratom plant. In the study published Tropical Life Sciences Research, scientists documented not only the anatomy, but the “micromorphology characteristics” of kratom plants collected from Malaysia. The study provided botanical evidence kratom is indeed a species of the Rubiaceae family, as provided in the recent mapping of the kratom genome.
Micromorphology is the examination of substances like soil or leaves on a microscopic level to describe and interpret components.
Leaves were collected from the field in Malaysia, and specific localities are listed in the study. Leaves were then fixed in a solution, and organized by thickness. Cuts from the middle parts of the leaves were cleaned, strained, and dehydrated. The microscopic photographs shown here were taken.
The first (color) set of photos show:
Transverse sections of M. speciosa. (A) Petiole TS; (B) Midrib TS; (C, D) Druses (Arrow); (E) Collenchyma cells (arrow); (F) Simple, unicellular trichomes observed on the adaxial side of the petiole TS; (G) Vascular bundle; (H) Additional vascular bundle; (I) Lamina TS; (J) Margin TS.(Ghazalli, 2021)
The characteristics of the kratom leaf anatomy are described in Table 2 of the study: Leaf lamina, or the thin flat green part of the kratom leaf. Leaf margin which is the outline or outer edge. The petiole or stalk that attaches the individual leaf to the stem. The midrib or the vein along the middle of the leaf. The trichrome which are tiny fuzzy bits you see growing from the leaf.
The second (black and white) set of photos show:
SEMs of adaxial and abaxial surfaces of leaf showing the surface sculpturing and the types of stomata of M. speciosa. (A) Abaxial surface; (B) Capitate glandular trichome; (C, D) Simple unicellular trichome with echinate ornamentation; (E, F) Arisen stomata; (G) Adaxial surface; (H) Adaxial surface ornamentation; (I) Wart; (J) Adaxial surface ornamentation (close up).(Ghazalli, 2021)
This study is open access, so if you’re a botany nerd or you like to spend hours Googling terms you’re unfamiliar with (like I have to), have at it! Or you can make a great T-shirt, avatar, or wall poster with these trippy photos.
Ghazalli, M. N., Md Sah, M. S., Mat, M., Awang, K., Jaafar, M. A., Mirad, R., Zaini, A. Z., Nordin, A., Rusli, N. M., Mohamad, S. S., & Dalee, A. (2021). Leaf Anatomy and Micromorphology Characteristics of Ketum [Mitragyna speciosa (Korth.) Havil.] (Rubiaceae). Tropical life sciences research, 32(1), 107–117. https://doi.org/10.21315/tlsr2021.32.1.7
Full Text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8054664/