Each considered as a separate species and constituting perhaps the most complete description of these species published in English, Mr. H. H. Hume’s characterization of the orange, sour orange, mandarin, pomelo, citron, lemon, and lime in his “Citrus Fruits and Their Culture,” is here reproduced without alteration. Some writers have grouped several of these as subspecies under one great comprehensive species, but, as Mr. Hume aptly says: “What advantage is there in throwing the sour orange, sweet orange, pomelo, kumquat, and a few other distinctly different trees into one conglomerate species * * * and then placing each of the aforementioned plants under this species as subspecies and varieties. Such a procedure is more likely to result in further confusion than order.”
The species of the genus Citrus that have come under the observation of the writer, with two exceptions, seem naturally to divide themselves into two groups,—(1) those with more or less united filaments and hypogeal cotyledons, and (2) those with free filaments, and (in all instances where there has been an opportunity for observations) with supra-terraneous, distinct cotyledons (fig. 1). In so far as these characteristics have been observed in the Philippine citrus fruits, long and broad-winged petioles are a third correlative feature distinguishing group No. 2; C. ichangensis recently described by Swingle from China also possesses this last feature, but has connate filaments. The alsem and alemow seem to be intermediate between these forms, the alsem being most closely related to those in the first division, the filaments being connate, while the cotyledons in some lots that have been propagated appeared above ground. The alemow is most closely related to group No. 2, the filaments being nearly always free. The general character of the talamisan together with the presence of hypogeal cotyledons tends to the belief that this species has more or less united filaments and thus would belong to the first group.
All descriptions have been made from living plant material either during tours of collection by the writer, or from plants grown at the Lamao experiment station from material sent to the Bureau of Agriculture from time to time since April, 1911. Also, all the material has been collected from plants growing in the yard of some Filipino and so may lay claim to having been domesticated. While this statement may not be altogether reliable it is interesting to note that in Bohol the Filipinos stated that the following trees grew wild in the forest: Among-pong, amontay, balincolong, biasong, canci, colo-colo, limoncito, limao, lombog, and samuyao.
While it is believed that the species described in this paper include most of the more distinctive Philippine citrus fruits, and several hitherto unknown even to the botanist, they do not by any means exhaust the Philippine forms of this genus. Several other forms have been noted, and constitute a part of the citrus collection at Lamao but are not here referred to, for the reason that the material on hand is too incomplete to warrant their description at this time.
Acknowledgements.—The writer is greatly indebted to Mr. E. F. Southwick, superintendent of the demonstration station at Cebu, for his untiring zeal in repeatedly forwarding sets of citrus fruits and budwood from Bohol and Cebu, and for his most valuable assistance during a collection trip made by him and the writer to Cebu and Bohol in May, 1914, without which it would not have been possible to obtain much of the data and material collected. All the species and varieties credited to Bohol were first called to the attention of the Bureau by Mr. Southwick. Mr. G. W. Weathersbee, formerly agricultural inspector of this Bureau, first called attention to the alemow and has also assisted in the collection of citrus material in Cebu. Mr. A. M. Burton, formerly superintendent of the Trinidad garden, Benguet, has forwarded fruits and budwood of the cabugao and other fruits. Mr. D. B. Mackie, entomologist of the Bureau, first called attention to a variety of alsem in Bontoc of superior quality. M. G. B. Mead sent the first specimens of Panuban.
Descriptions and Comments.
Citrus aurantium L. Orange.
A tree 7.5 to 12 meters in height, with a compact, conical head; bark grayish brown; thorns generally present, 12 to 50 millimeters long, sharp, stout; leaves oval or ovate oblong, 7.5 to 10 centimeters long, smooth, shining, somewhat lighter below than above, margins entire, or very slightly serrate; petiole 12 to 25 millimeters long, slightly winged (occasionally with quite a broad wing); flowers axillary in clusters of one to six, white, sweet scented, smaller than those of C. vulgaris; calyx cupped; sepals four to five, awl-shaped, thick, greenish, persistent; petals usually five, oblong, 25 to 31 millimeters long, thick, fleshy, recurved; stamens twenty to twenty-five, hypogenous, filaments flattened, united in groups, shorter than the petals; pistil distinctly divided into stigma, style and ovary; stigma knob-like; style long and slender; ovary rounded, 10 to 14 loculed; fruit globose to oblate, light orange to reddish; rind smooth; pulp juicy, subacid; juice sacs spindle shaped, sometimes larger than those of C. vulgaris; seeds few or many, oblong ovoid, planoconvex, generally broad, wedged or pointed at the micropylar end, marked with oblique ridges surrounding one or two plain areas. Native to China or Cochin China.
While the orange is nowhere planted in orchards it is fairly well distributed. Judging from the prevalence of the citrus fruits in the markets in the various parts of the Archipelago it ranks fifth in production, as compared with the mandarin, pomelo, lime, and calamondin, the only citrus fruits beside the orange that may claim to be of any economic importance even from a Philippine point of view. Excepting a few budded trees of recent importation or distribution by the Bureau of Agriculture all trees are seedlings and nearly always the fruit is poor in quality.