A spiny tree, attaining a height of 6 or more meters; young growth green with a tinge of purple; leaves 9 to 13 centimeters long, 3.5 to 5.5 centimeters broad, ovate to short ovate, bicrenate, dark green and glossy; base rounded, apex emarginate; petiole 4 to 7.5 centimeters long, 2.9 to 5 centimeters wide, oblong, with a broadly acute to obtuse base; wing area nearly equal to or frequently exceeding the leaf area; flowers 20 millimeters across, in axillary clusters of 2 to 6; pedicel slender; calyx small, not cupped; petals 4 to 5, white, with a tinge of purple on the outside; stamens 21 to 26, free, equal; ovary subglobose, 3 millimeters long, 11 to 14 loculed; style short, 1 millimeter long, distinct; fruit 48 to 55 millimeters long, and about 50 millimeters in transverse diameter, irregularly globose to oblate, usually compressed towards base, ending in a small nipple, more or less wrinkled, greenish lemon yellow; pulp greenish, fairly juicy, acid, scarcely edible; juice cells small, short, containing a small greenish nucleus; seeds small, oblong, reticulate. This plant is the C. torosa of Blanco, which has been considered a synonym of C. histrix, and here raised to the rank of a subspecies. A comparative study of C. histrix and the variety torosa shows considerable differences between the two. C. histrix is generally larger in all parts; the wings of C. h. torosa are oblong, maintaining an almost equal width over a large part of the petiole, ending in a rounded to a broadly acute base, while in C. histrix, and in fact in all the species herein described with free stamens, the wings are more or less cuneate to elongate cuneate or oblong-spatulate, ending usually in an acuminate, sometimes an acute base, the one closest approaching the C. h. torosa in this respect being the "balincolong," referred to C. micrantha. The flower of C. h. torosa corresponds with that of C. histrix except that the former has 21 to 26 stamens as compared with 30 to 36 in C. histrix, which also averages more locules to a fruit. B. A. No. 3665, 3666 (Batangas). Citrus micrantha. Biasong. (Pls. Vc, VIb, VIIc.)