柑橘屬常綠喬木，1858年起源於美國加州，在許多生產檸檬的國家是最主要的栽培品種。具有枝少刺或近於無刺的特徵，嫩葉及花芽暗紫紅色。互生卵形或橢圓形葉。單花腋生，花具香味，苞片淡紫色。果橢圓形或卵形，有尖凸，果皮厚，通常粗糙，成熟黃色。能全年開花結果，因此得名。

An evergreen tree in the genus Citrus, originated in California in the United States since 1858. It is the main variety producing lemons in many countries. It has few thorns or nearly thornless on the branches; the leaves and flower buds are dark purple-red. Leaves alternate, ovate or oval. Flowers solitary and axillary, aromatic, bracts lavender in color. Fruits oval or ovate, with a pointed convex, rind thick and often coarse, mature yellow. It produces flowers and fruits year-round, which gives rise to the Chinese common name.

喜日照充足，日照不足或水分太充足易造成不開花結果。適宜在富含腐植質且排水良好的砂質壤土中生長。適合在肥沃、深厚以及疏鬆的土壤中種植，土壤要具有一定的酸性。以種子、嫁接或扦插繁殖。

It thrives in sunny conditions, lacking of sunlight or excess water will inhibit flowering and fruiting. Suitably grown in fertile, deep, loose, well-drained, rich in humus and moderately acidic sandy loam soils. Grown from seeds, grafts or cuttings.

可作庭園景觀樹、盆栽果樹。果可食，富含維他命Ｃ，可榨汁製作冷飲或食物調味用。可製果乾泡茶或製成蜜餞。

Suitably used as garden ornamental trees and potted fruit trees. The fruits are edible and rich in vitamin C; they can be squeezed to make cold drinks or as food seasoning, or made into candied fruits or dried fruits.