Here is a quick guide to the five species of Cucurbita for those interested in identifying and growing them, particularly for seeds.
Many varieties of Cucurbita moschata occur with quite different fruit forms. They may be bell-shaped, a flattened round shaped or have elongated curved or straight necks.
Members include: Butternut; Jap; Cheese pumpkins; Crookneck (Golden cushaw).
Varieties within this group often have bright orange skin and hard, woody, distinctly furrowed stems. However, the group also includes gourds, vegetable marrow, pattypan summer squash, zucchini and summer crookneck squash.
Members include: Vegetable spaghetti; Hull-less seeded (Naked seed) types; and Pie pumpkin.
Note: The terminology 'gourd' simply refers to the use the fruit is put to. Gourds belong to several plant families and may not be Cucurbita at all.
These are generally the big pumkins.
Members include: Jarrahdale; Qld. Blue; Atlantic Giant; Golden Nugget; Baby Blue; Triamble; Hubbard; Turban; Banana; and Buttercup.
C. mixta was once included within C. moschata, but there are some differences that distinguish them, including flesh texture. See below for how to tell them apart.
Members include: Kempsey pink
There is only one commonly cultivated fruit in this species – Chilacayote.
Also known as fig-leaved gourd, malabar gourd, malabar squash, pie melon or shark fin melon.
The stems and seeds of genus Cucurbita help to identify the species.
C. maxima - has a soft and round & corky stem. The seeds are thick with cream coloured margins and a thin cellophane coating.
C. mixta - the stem is hard, hairy, is five angled and flares out slightly at the fruit end. Seed is white or tan with a pale margin and cracks in the seed coat on the flat sides of the seeds. Seeds also have a thin cellophane coating.
C. moschata - has a hard, hairy and slightly angular stem that flares noticeably at the fruit end. Seeds are small, beige and have a darker beige margin.
C. pepo - has a hard, furrowed stem with five distinct angles. It's leaves are harsh textured, unlike the soft texture of the other species. Seeds are cream coloured with a white margin.
There are also differences in the flowers that can be looked up if the above does not clearly identify the species.
Generally cross-pollination between the five cultivated Cucurbita species does not occur. However care should be taken if growing C.mixta and C.moschata together as there are some reports of these types crossing, although other sources claim they do not cross.
If multiple varieties from the same species are grown they must either be hand pollinated or separated by at least 400m in order to gain seed that will be true to type.