Extrafloral Glands of Cucurbitaceæ

Abstract

I HAVE already pointed out¹ that quite a good number of species of Cucurbitaceæ are provided with well engineered devices for exudation of surplus water and waste substances. These plants, being primarily moisture loving, have structures especially suited to exudation of aqueous fluids which are absorbed in quantity in excess to the requirement, physiological conditions being very favourable for rapid absorption. The genera Coccinia, Luffa, Lagenaria, Momordica, Cucurbita, etc., develop extrafloral nectaries. In Coccinia cordifolia (Linn.) Cogn. a few glistening glands are present on the lamina round about the basal region of the midrib on the adaxial leaf surface ; in Luffa acutangula (Linn.) Roxb. and L. cylindrica (Linn.) Roem. these glands are often found scattered all over the lamina besides a special fleshy glandular probract being developed at the base of the peduncle of the male and female inflorescences ; in Lagenaria vulgaris Ser. (Lagenaria leucantha (Duch.) Rusby) two bilateral glands are present at the remote end of the petiole and in Momordica cochinchinensis (Lour.) Spreng. a few are found at the petiole end or on the lateral marginal costa at the leaf-base ; in Cucurbita pepo Linn., C. maxima Duchesne and C. moschata Poiret minute club-shaped glands do develop at the abaxial leaf surface.