Manihot tristis subsp. saxicola (Lanj.) D.J.Rogers & Appan

  • Authority

    Rogers, David J. & Appan, S. G. 1973. Manibot, Manihotoides (Euphorbiaceae). Fl. Neotrop. Monogr. 13: 1-272. 1 chart. (Published by NYBG Press)

  • Family

    Euphorbiaceae

  • Scientific Name

    Manihot tristis subsp. saxicola (Lanj.) D.J.Rogers & Appan

  • Type

    TYPE. Lanjouw, J. 955: Suriname: Monte dicto Voltzberg ad saxis graniticus, 23 Sept 1923 (holotype, U; isotypes, F, MO, NY, U-2, US).

  • Synonyms

    Manihot saxicola Lanj.

  • Description

    Description - Erect shrubs, 1.0-3.0 m tall. All plant parts glabrous. Roots with intermittent globose tuberous swellings, ca 7.0 cm in diam (Shulz & Donselaar 10593) resembling tuberous roots of Manihot esculenta (Pires & Westra 48837). Young stems purplish tinged, devoid of any bloom. Stipules semifoliaceous, 1.25 cm long, 0.2 cm wide, persistent, margin laciniate; lamina narrowly peltate, width between basal edge of lamina and petiole-lamina junction 0.2 cm; abaxial lamina surface pruinose; palmately 5 lobed, occasionally with 2 more smaller lobes, ca 8.0 cm long, ca 2.5 cm wide, obovate, rarely pandurate, base of lobes more than 0.3 cm wide, lamina between base of sinus and petiole-midrib junction more than 0.3 cm. Inflorescence a moderately branched panicle with ca 25 flowers; peduncles purplish tinged; tepal yellowish green. Fruits ca 1.25 cm long, blackish brown, apex rounded, slightly winged, dehiscence septicidal. Seeds 1.0 cm long, oblong, with a moderately prominent caruncle.

  • Discussion

    This subspecies shares with subspecies tristis the interesting habitat preference of granitic outcrops. To our knowledge, only one other species of the genus, Manihot leptopoda, is found on this type of substrate. These should, therefore, be important in breeding programs with M. esculenta to improve culture on soils of granitic origin.

    M, tristis subspecies saxicola, first described as a separate species in 1939, by Lanjouw, was brought into cultivation in Buitenzorg shortly after the species was discovered. The growth pattern under cultivation is much more erect than the typical pattern as a wild plant (see Lanjouw 1939 photographs). Lanjouw reported 2.3% "albumin" in the roots on a fresh weight basis. Bolhuis (1953) used this plant in breeding programs in Java in attempts to increase protein content of the roots of M. esculenta. Roots of F1 seedlings of the cross M. esculenta X M. tristis subsp saxicola produced approximately 2% protein, but in clones propagated from these seedlings, protein content fell back to typical levels (ca 1%).

  • Common Names

    Boesi-ingi-kasabu, Maynoc, wilde cassava

  • Distribution

    (Fig 31C). Suriname and Brasil, Amapa Territory.

    Brazil South America| Amapá Brazil South America|