Stems terete, striate, with small bullate tubercles, more dense when mature. 茎圆柱状,具条纹,有小小瘤,成熟时非常紧密。
Adaxial surface appearing bullate, deep green, slightly shiny, glabrous; 正面似乎具泡状隆起,深绿色,稍发亮,无毛;
Corolla white, white flushed pink, rarely pale yellow; calyx red or tinged red; adaxial leaf surface not bullate. 花冠白色,白色的奔流的粉红色,很少浅黄;红色的或微染的花萼红色;叶正面不具泡状隆起。