Mammillaria theresae


Yavia cryptocarpa

This type of fruit are characteristic of few sort of cactus , for example Mammillaria of the Series Longiflorae (e.g. M. theresae, M. saboae, …) and Yavia cryptocarpa.
They are retained within the plant body for several years or for the whole life cycle of the plant, and frequently (in Mammillaria) the fruit and seeds will be released only at the death of the plant after the disintegration of the old  stem. After the flower is finished and dropped off, the stem closes over the fruit and the fruit/seed slowly ripens within. The next year, or years, the fruit may remain within the body at the axil, or may poke out a bit.

Seeds of cryptocarpic species  are equipped to maintain  their vitality for many years, they contain inhibitors that preserve them from premature germination, generally fresh seeds won’t germinate very well, only old seeds do.
It is possible to collect fruit and seeds from this plants only by means of a thin pointed forceps. The complete germination of this kind of seeds may take several years (occasionally a seed will sprout unexpectedly after 5 or 8 years!) Because of the above peculiarity, seed of cryptocarpic Mammillaria (Series Longiflorae)  is seldom available from commercial sources, as its collection is unusually labour intensive. In Yavia the ripen fruit will be slowly expelled by the growing of the plant during the humid season when the plant body swell up.