The genus Thelocactus 

Thelocactus leucacanthus

Scanning electron microscope micrographs of Thelocactus leucacanthus seeds. Seeds are medium-sized, with the longest axis of 1,6-2 mm and a diameter of 1,3-1,4 mm. The hilum-micropylar border is expanded around and constricted above the hilum. The micropyle lies outside the hilum or on its border. Anticlinal boundaries are raised and straight. Outer periclinal walls are tabular with a verrucose surface.

Thelocactus leucacanthus (40x) Photo: A. Mosco		Thelocactus leucacanthus (40x) Photo: A. Mosco
Thelocactus leucacanthus The hilum-micropylar region with the micropyle set ouside the hilum. (160x) Photo: A. Mosco		Thelocactus leucacanthus (320x) Photo: A. Mosco