In Sarawak, Malaysia, simple methods for estimating the leaf area of sago palms were examined using a total of eight leaves of the lower, middle, and upper three leaves for first and seventh year plants after trunk formation and the middle and upper two leaves for fourth year plant after trunk formation. Taking into account the positions of attachment from the lower to the upper of the eight leaves, the leaf area of half of the leaflets was actually measured, and this was doubled to obtain the measured leaf area (A). For each leaf, three methods of estimating leaf areas—(B) the longest-leaflet area × the number of leaflets, (C) the longest-leaflet length × the maximum width × the number of leaflets, and (D) the longest-leaflet SLA (specific leaf area) × leaflet weight per leaf—were applied, and the leaf areas were determined and compared with the measured leaf area (A). The average A/B, A/C, and A/D values of the eight leaves were 0.65, 0.54, and 1.03, respectively, and the coefficients of variation were as low as 3.7–8.7%. From these results, it seemed that the leaf area of the sago palm can be easily estimated by multiplying the values obtained with methods (B) to (D) mentioned above by the correction factors of 0.65, 0.54, and 1.03, respectively.

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 The sago palm (Metroxylon sagu Rottb.) forms phytoliths (biogenic opal silica) in all organs as a result of silicon uptake from soil. The phytolith assemblages in the sago palm were extracted using a dry combustion method with a muffle and described based on morphology and ornamentation according to the International Code for Phytolith Nomenclature 1.0 and 2.0. Using an optical microscope, spheroid (globular) echinate phytoliths, of which the morphology is highly diagnostic with minor exceptions, were observed in a leaflet of M. sagu from the Philippines. Studies of the M. sagu phytolith, which showed spheroid, echinate grains from 2.5 to >22.5 μm in diameter, with a peak range of 10 to 12.5 μm, could provide a tool for documenting the biosilicification of phytoliths and archeological evidence of sago cultivation before rice in coastal areas of the Philippines.

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 Growth characteristics and starch productivities of the sago palms growing in Pontianak, West Kalimantan, Indonesia were investigated. Sago palms were growing along the tributaries of the Kapuas River in semi-cultivated/cultivated states. There were two folk varieties, Bemban and Buntal (hereafter referred to as varieties), both of which are non-spiny types; the characteristics of the varieties were distinguished in features such as their suckering ability, crown angles, and trunk length and diameter. Both varieties were estimated to be 10-12 years from harvest. As a result of a sampling survey at the appropriate harvest stage (bolting to flowering stage), Bemban was significantly superior to Buntal in trunk length, leaflet length, width and area, and leaf area. There were no significant differences between the varieties in dry matter, total sugar, and starch percentages in the pith. Moreover, a varietal difference was also not observed in the pith dry weight; therefore, there was no significant difference in starch content (yield), although the starch content of Bemban (326kg) was slightly higher than that of Buntal (278kg). There were no differences between the two varieties in the macronutrient contents in the leaflet and pith except for the Mg content in the leaflet. We concluded from these results that the two varieties of sago palms growing in Pontianak were not significantly different in starch and macronutrient contents in pith, although some growth characteristics were significantly different.

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 The palm family generally has characteristic phytoliths with many conical projections. Diagnostic, amorphous spheroid, echinate phytoliths are present in all organs of the sago palm (Metroxylon sagu Rottb.), which constitute approximately 8–9% of leaflet dry weight. For phytolith observation, transmitted-light (TLM) and scanning electron microscopy (SEM) were used at x400 and x1000 magnifications. The terminal angles and length of conical projections were calculated according to Heron’s formula. The mean maximum diameter of phytoliths and the mean number, mean terminal angle, and mean length of conical projections of M. sagu were 13.2 μm, 26.0, 84.0°, and 0.54 μm, respectively, under TLM. Meanwhile, the phytoliths of M. sagu were 15.1 μm of the mean maximum diameter of phytoliths, 21.6 of the mean number of conical projections, 91.4° of the mean terminal angle of conical projections, and 1.45 μm of the conical projection lengths under SEM. It is possible to utilize spheroid echinate morphology, conical projections arranged at the periphery, and terminal angles and lengths of conical projections as indicators of the identification of M. sagu phytoliths.

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