II.2. SQUASHES, PUMPKINS, ZUCCHINIS, GOURDS (CURCURBITA SPECIES) – 103
also represent a means by which Cucurbita seeds are dispersed. Generally, this occurs
through ingestion of fruits with seeds; with the seeds then being excreted at a distance
from the initial point of ingestion. In many areas of the world, Cucurbita fruits are used
as fodder. For example, in tropical regions, domestic animals such as donkeys and horses
will consume Cucurbita L. fruits and vines when fodder is scarce at the end of the rainy
season (Mariano and Dirzo, 2002).Seed and germination
The seeds are surrounded by several layers of tissue. The most external layer derives
from the internal epidermis of the carpel (endocarp) and generally swells with water; the
internal layer derives from the testa (seed coat) and develops from the ovule’s integument
and nucellus (Zomlefer, 1994).Table 2.4. Phenology and life cycles of 20 Cucurbita taxaTaxa Phenological notes in Mexico
Annuals C. argyrosperma argyrosperma
C. argyrosperma ssp. sororia Flowers from June to January and begins to fructify in August, but it is
more common to find mature fruits from November or December
C. ficifolia
C. maxima
C. maxima ssp. andreana Produces fruits in September and from February to April
C. moschata
C. pepo ssp. pepo
C. pepo ssp. fraterna
C. pepo var. texana Flowers and fruits between July and November
C. ecuadorensis It is possible to find male flowers and fruits between February and July
C. lundelliana It is possible to find populations with flowers of both sexes.
Mature fruits are more surely found between November and February
C. okeechobeensis ssp. okeechobeensis Flowers and fruits between May-June and January, and the mature
fruits from October onwards
C. okeechobeensis ssp. martinezii Flowers and fruits between June and January or February, and mature
fruits can be found from October onwards
Perennials C. digitata Populations with flowers and fruits occur all year round
C. cordata Populations with flowers and fruits occur all year round
C. palmata Populations with flowers and fruits occur all year round
C. foetidissima Populations with flowers and fruits occur all year round
C. pedatifolia Flowers and fruits between August and November and mature fruits
from October onwards
C. radicans Flowers and fruits between May-June and December, and the mature
fruits from October onwards
C. scabridifolia Flowers and fruits from June-July and until December, and the fruits
from August or September
Seeds are oval, oval-elliptical or oval-lanceolate, compressed or more or less
tumescent or inflated, with a smooth or sometimes scarified or scarred centre which can
be white, cream-colored, greenish-grayish-blue or black, with or without marked or
differentiated margins, and these of the same or different colour and/or texture as the
centre of the seed.
The number of seeds produced per fruit varies among the species. Lira, Andres and
Nee (1995) report that some domesticated varieties of C. ficifolia have average-sized
fruits with more than 500 seeds. C. argyrosperma produces more than 250 seeds per fruit
(Merrick, 1990). The wild species C. pepo var. texana also can produce more than
250 seeds per fruit (Avila-Sakar, Krupnick and Stephenson, 2001).