Sesamum alatum Thonn. (Introduced) (Angola, Benin, Botswana, Burkina, Cameroon, Caprivi Strip, Chad, Egypt, Eritrea, Ethiopia, Ghana, Guinea, India (I), Kenya, KwaZulu-Natal, Mali, Mauritania, Mozambique, Namibia, Niger, Nigeria, Northern Provinces, Senegal, Sudan, Swaziland, Western Sahara, Zambia, Zimbabwe; Introduced in as per POWO)
Sesamum indicum L. (Native to Assam, Bangladesh, India, Lebanon-Syria, West Himalaya; Introduced to Afghanistan, Alabama, Andaman Is., Angola, Belize, Benin, Bolivia, Borneo, Brazil North, Bulgaria, Burkina, Burundi, California, Cambodia, Cameroon, Central African Repu, Chad, China South-Central, China Southeast, Congo, Costa Rica, Cuba, Cyprus, East Himalaya, Egypt, El Salvador, Eritrea, Ethiopia, Fiji, Florida, French Guiana, Gabon, Galápagos, Gambia, Georgia, Ghana, Greece, Guatemala, Guinea, Guinea-Bissau, Guyana, Hainan, Honduras, Iran, Ivory Coast, Japan, Kazakhstan, Kenya, Korea, Krym, KwaZulu-Natal, Laos, Lesser Sunda Is., Liberia, Libya, Louisiana, Madagascar, Malawi, Malaya, Mali, Masachusettes, Mauritania, Mauritius, Mexico Gulf, Mexico Southwest, Missouri, Morocco, Mozambique, Myanmar, Nepal, New Jersey, New York, Nicobar Is., Niger, Nigeria, Northern Provinces, Ohio, Pakistan, Pennsylvania, Peru, Philippines, Rwanda, Saudi Arabia, Senegal, Sierra Leone, Somalia, South Carolina, South European Russi, Spain, Sri Lanka, Sudan, Suriname, Swaziland, Tadzhikistan, Tanzania, Texas, Thailand, Togo, Transcaucasus, Trinidad-Tobago, Turkey, Turkey-in-Europe, Uganda, Ukraine, Uzbekistan, Venezuela, Vietnam, Wisconsin, Yemen, Yugoslavia, Zambia, Zaïre, Zimbabwe as per POWO)
Sesamum prostratum Retz. (S-India, Sri Lanka)
Systematics and evolution in Sesamum L. (Pedaliaceae), part 1: Evidence regarding the origin of sesame and its closest relatives– Dorothea Bedigian- Webbia 70(1):1-42 · January 2015:
(Abstract: Morphologically leaves of both look quite different. But in view of the paper you stated I have to merge both as per abstract:
Recent molecular studies demonstrate that Sesamum sect. Sesamum, deﬁning the largest genus of Pedaliaceae, holds two subspecies: the oilseed crop Sesamum indicum, and the crop’s progenitor Sesamum indicum subsp. malabaricum, and fail to support the idea that cultivated sesame originated from the African Sesamum latifolium. Therefore, in this updated classiﬁcation, Sesamum sect. Sesamum is re-circumscribed to contain the Asian progenitor species of sesame. As a result, these data do not support the current infrageneric classiﬁcation system; instead, these molecular results offer alternative implications with regard to the evolution of the genus and provide a basis for developing an updated taxonomy that is consistent with underlying phylogenetic relationships. Each clade is recognized as a section, thereby retaining valuable information on evolutionary relationships while minimizing nomenclatural changes. These analyses also reveal that section Sesamum is sister to Sesamum sect. Chamaesesamum. That section holds two species, Sesamum laciniatum and Sesamum prostratum, that have frequently been treated as distinct, but are combined here).
Key to the subspecies of Sesamum indicum L.
1. Plant generally 25–110 cm high, branched or unbranched, depending on cultivar. Living plant colour yellow-green, fern green, shamrock green, emerald
green, forest green, jade green, sea green or dark green with purplish hue. Lower leaves vary according to cultivar – occasionally divided (Figure 5), tripartite, with toothed margins (Figure 6), some with leafy outgrowths at base of leaves above petiole (Figure 7); many cultivars with lanceolate, or simple ovate leaves and entire margins (Figure 7). Upper leaves (bracts) linear with entire margins (Figure 7). Corolla 15–33 mm long, violet, pink or white; length of lower lobe equal to, or 2–10 mm longer than other lobes, depending on cultivar; colour variable, white, light pink, pale lavender to deep purple, or with pale lavender lines, pigmentation throughout the lower lobe or along the margin only; exterior and interior coloration ranges on scale 1–10, from 1–8, in line with cultivar; some with linear markings, some tinted only at lower margin of lower lip, of variable intensity and amount of surface area covered. Extrafloral nectaries 1–1.2 mm in diameter. Capsule 15–50 mm by 6–14 mm; bicarpellate (Figures 8–10) or tetracarpellate (Figures 11, 12), texture papery to woody (variable). Seeds 1.5–4 mm long; colour variable – white, ivory, beige, tan, mustard yellow, brick red, various shades of brown, grey or black; egg- to teardrop-shaped, surfaces smooth or granular, seldom transversely or reticulately rugose, with edges sloping; seeds not dormant ………. 1. subsp. indicum
2. Plant often reaches 200 cm high, typically branching profusely. Living plant colour dark green, often with purplish hue. Lower leaves divided, in less developed leaves undivided, margins serrate, without leafy outgrowths at base of leaves above petiole. Upper leaves cordate. Corolla 22–55 mm long, generally white to pale purple; lower lip 10–15 mm long, and dark purple, the colour ranking 10, on a scale 1–10, and occupying entire lower lip. Extrafloral nectaries 2– 3 mm in diameter. Capsule 20–25 mm by 6 mm; only bicarpellate, woody. Seeds 2–2.5 mm long; colour dark brown or black, broadly ovate, surfaces conspicuously reticulately rugose, with distinct sharp edges, sides broad, all sides conspicuously transversely or reticulately rugose; seeds markedly dormant ……………… 2. subsp. malabaricum (Not accepted as per Flora of North America Editorial Committee (2019). Flora of North America North of Mexico 17: 1-737. Oxford University Press, New York, Oxford as per POWO)
A New Combination for the Indian Progenitor of Sesame, Sesamum indicum (Pedaliaceae)– Dorothea Bedigian- Novon Vol. 23, No. 1 (April 2014)pp. 5-13:
(Abstract: The new combination Sesamum indicum L. subsp. malabaricum (Burm.) Bedigian (Pedaliaceae) is provided for the progenitor of sesame. Both lectotype and epitype for S. malabaricum Burm., the basionym of the new combination, are designated herein. A plate (van Rheede tot Draakestein, 1689: tab. 55) mentioned in the original protologue (Burman,1769) is designated here as the lectotype for S.indicum L. subsp. malabaricum (Burm.) Bedigian. Previously published evidence about the relationship of S. indicum and S. malabaricum summarized here
and shared morphological traits described here provide a foundation for the recognition of this taxon at the changed rank of subspecies)
KEY TO THE SUBSPECIES OF SESAMUM INDICUM L.
Flora of Eastern Karnataka, Volume 2 By N. P. Singh (1988)- Descriptions of
Sesamum laciniatum (syn. of Sesamum prostratum)
Sesamum orientale L. is a synonym of Sesamum indicum L.)
Descriptors for Sesame (Sesamum spp.) By Bioversity (2004)- Details-
Sesamum laciniatum (syn. of Sesamum prostratum)
Flora of Guntur District, Andhra Pradesh, India (1998)- Details with keys–