Plants of the alsem have never been seen by the writer in the provinces, the description of the plant having been made from budded plants growing at Lamao, propagated from material collected in Bulacan. The trees have a long flowering season, as fruits are offered in Manila throughout the summer to late in autumn. The variation in the fruit is very great, some being of little value, while others are extremely thin skinned, well flavored, juicy, aromatic, with less rag than perhaps any citrus fruit that has been examined by the writer. The floral characters correspond closely to those of the mandarin, which the fruit in some forms also resembles in appearance and in its loose-skinned character. Flavor and aroma place the alsem in close relationship with the cabuyao, C. histrix, and it is a curious fact that the Tagalogs always call it "cabuyao." In common with the cabuyao it is frequently infested with the rindborer, Prays citri, while the mandarin is practically immune to this pest. An analysis made by the Bureau of Science in November, 1912, of alsem fruits purchased by the writer in Manila gave the following results: Weight of-- Grams. Fruit 56.5 Peel 15 Seed 1.5 Pulp (rag) 13.5 Juice 26.5 Analysis of juice. Per cent. Acidity (citric) 5.41 Sucrose None. Sugar 2.41 Protein .33 Ash .39 Analysis of pulp. Per cent. Acidity (citric) 2.73 Protein 1.03 Ash .58 The alsem was considered a variety of the mandarin in Bulletin No. 27, Plate IV, but a closer study of the plant and fruit shows that it differs so greatly from all other Philippine species of the genus as to be entitled to specific rank, and it has been named in honor of Dr. H. J. Webber, director of the citrus experiment station, Riverside, California, the association with whom, in connection with his citrus and pineapple breeding work, more than any other cause influenced the writer to take up the improvement of tropical economic plants. The Bontoc local name "alsem" is here proposed as the vernacular name for C. webberii. In previous publications by the writer it was called the "mandarin lime," which is hardly suitable, however, since while it has certain resemblances to the mandarin yet is distinct from it, and again, its only resemblance to the lime lies in its acidity and ade-making qualities; moreover the name "mandarin lime" is too long for popular use. B. A. No. 853 (Bulacan), 2275 (Manila), 4292 (Bontoc). Citrus webberii var. montana. Cabugao.