A tree attaining a height of 6 meters, of upright growth, and rather long, stout, sharp spines; leaves 14 to 18 centimeters long, 6 to 8 centimeters wide, elliptical to ovate, crenate to serrate; base rounded; apex acute; petioles 18 to 40 millimeters long, broadly winged, wings frequently exceeding 35 millimeters in width; flowers 4 to 7, in compact cymes, sessile, 18 to 22 millimeters in diameter; calyx cupped; petals 4 to 5, oblong; stamens 26 to 30; filaments nearly always free; ovary small, 13 to 16 loculed; style distinct; stigma club shaped, small; fruit 85 to sometimes exceeding 100 millimeters in length, attaining a weight of 500 to 800 grams, subglobose to roundish oblong, more or less compressed towards base, which is nippled and with stem inserted in a shallow cavity; apex flattened with a circular depression around the raised stigmatic area; surface greenish lemon yellow, rather rough, with transverse corrugations; oil cells small, sunken; skin comparatively thin; pulp grayish, rather dry, sharply acid, lemon flavored; juice cells rather slender, long, and pointed; seed medium large, short and plump, smooth, sometimes beaked.
The alemow is a very rare fruit occurring in cultivation in Cebu, and considered inedible even by the natives. The description of the flowers was made from fresh specimens collected in May. The tree is said to bloom later in the year during the rainy season having then larger flowers. Partly grown fruit was then seen on the tree and since mature fruit has been examined by the writer from December to late in February the alemow is evidently nearly if not quite everbearing.
The principal distinguishing features in this species are the large, broad leaves, the comparatively short but quite broad-winged petioles, the free rarely united filaments, and the quite large, peculiarly shaped fruit; it is thus apparently one of the links between the two branches of the genus, one of which has the filaments more or less united and the other the filaments free, being in the first group most closely related to the pomelo.
The alemow was first forwarded to the writer under the name of colo: Bulletin 27, Plate XIV.
B. A. No. 2510, 2377, 3677, 4820 (Cebu).
Citrus southwickii. Limao.
A thorny tree, with dense head and drooping branches, attaining a height of 6 meters; spines small but sharp, leaves 9.5 to 14 centimeters long, 36 to 53 millimeters broad, ovate to roundish ovate, conspicuously crenate, dark green and shining above, leathery; base acute; apex acute to obtuse, frequently emarginate; petioles 35 to 70 millimeters long, the wings 25 to 30 millimeters broad in large leaves, the average wing area somewhat less than half of the leaf blade; flowers 2 to 6, in compact axillary or terminal cymes, sometimes solitary, 14 to 20 millimeters in diameter, white, with trace of purple on the outside; calyx very small; stamens 22 to 28, free; ovary globose to oblate; locules 15 to 19; stigma almost sessile; fruit 45 to 55 millimeters long, 55 to 65 millimeters in equatorial diameter, oblate, with shallow cavity at apex, smooth, with slight longitudinal corrugations; lenticels sparse, small; oil cells usually raised; skin thin; pulp fairly juicy, sharply acid, bitter, with distinct aroma from C. histrix; juice cells short, plump, granulate, small, containing a small, greenish nucleus; seeds numerous.
The limao, though rare, is not uncommon in Bohol, where it is cultivated and has also been collected by the writer in Baganga, Mindanao. The flowers appear late in April and during the early part of May, with the fruit ripening in January and February; a few fruits nearly full grown were collected in May. No. 2049 has flowered irregularly from May to December. The fruit is not eaten, but used in washing by the Boholanos and is of no economic importance. The tree is evidently quite drought resistant, and succeeds well in very scanty soil underlaid with limestone.
The limao belongs in that group of the citrus fruits having free filaments, the most conspicuous characters being the compact growth of the crown, the dark-green, thick, and distinct leaves, the almost sessile stigma, and the attractive, oblate, regular-shaped fruit with its many locules, exceeding in number those in all other citrus fruits known to the writer. This species has been named in honor of Mr. E. F. Southwick, elsewhere referred to in the paper.