In article ,
Iris Cohen wrote:
Cucurbita moschata or C.maxima is generally better for this than C.pepo
What is the difference? Which is the big round orange thing usually called a
pumpkin?. Isn't that what they sell in a can?

There are four domesticated species of Cucurbita grown in North America
and at least three of them have cultivars that produce fruits that look
like the traditional pumpkin, and are called pumpkins here. The other
cultivars produce fruits that are called squash in this part of the
world, but in some others, e.g. Jamaica, all Cucurbita fruits are
called pumpkins.

None of the four species cross, but the Japanese have some sterile
hybrids of C.moschata and C.maxima. I tried making this cross and got
fruits full of empty seeds, but I often get a lot of empty seeds
anyway in normal fruits, probably because my season is so short.

There are clear botanical differences which are easy to see once you
know what to look for. I used to have a list of them with proper
technical terminology, but I'll try to wing it here. If someone can
point me to better descriptions, I'd appreciate it.

C.mixta -- I don't know much about this one since it doesn't grow in
this climate, and doesn't appear to be in international commerce.
Cultivars are sometimes called cushaws or cushaw pumpkins.

C.moschata -- The most common cultivar is the butternut squash, but
there are others, including some of the "cheese pumpkins" named for
their shape, resembling a large wheel of cheese. There are some
Japanese cultivars with other sizes and shapes. IIRC, commercial
canned pumpkin is made from a large pumpkin-shaped cultivar of this
species. The leaves are relatively small and somewhat fuzzy. The
seeds are small and have a thin shell. The stems and petioles are hard
and very resistant to squash vine borer. The flesh is orange.

C.maxima -- Most of the large squashes are in this species, e.g.
hubbards and hubbard types, as well as buttercups, Turk's turban,
banana squashes, and both big pumpkins and huge ones like the Hungarian
and Atlantic Giants. They have bigger leaves and spongy porous hollow
stems that are very attractive to squash vine borers. The seeds are
large and have a thick but not hard white shell. The flesh is usually
dark orange and has a "melting" (i.e. moist and not stringy) character
although some Japanese cultivars have a drier, flaky sort of flesh.

C.pepo -- Most summer squashes, e.g. zucchini, pattypans and crooknecks
are in this species, as are acorn (aka pepper) squashes, vegetable
spaghetti, delicata squash and many of the small ornamental gourds and
mini pumpkins. Some have persistent silver markings on the leaves.
This is the only species, AFAIK, that has the trait for a real "bush"
habit, i.e. extremely short internodes, although most cultivars other than
summer squash don't have it, and there are so-called bush varieties of
the other species that are just short vined rather than short in the
internodes. The flesh is usually relatively pale, yellow rather than
orange and the seeds are small and hard shelled.

You can distinguish the species in the supermarket by examining the
peduncle where it attaches to the fruit. Unfortunately, I can't
describe this correctly, although I can see it. If you compare this
area in fruits that you know the species of, e.g. a butternut, a
buttercup and an acorn squash, you'll see what I mean.

Resistance to squash vine borer is very important to me
since it's a major pest here. While it's not as much a problem with
zucchini (C.pepo) as with C.maxima, I was delighted to find a
C.moschata cultivar, Tromboncino Rampicante. which makes a good zucchini
substitute immature, but is kind of stringy as a winter squash. I gave
some to my neighbours, and it seems to have crossed with normal
butternuts, and they now grow these monster meter-and-longer tubular
butternut looking squash. I don't know what they do with them, but I
see them in back yards at some distance from mine.

Before I close this excessively long essay about one of the plants I
most enjoy growing, I'd like to ask my world-wide audience whether
they've ever seen a butternut squash with a netted green pattern
overlaying the usual tan color. I bought one at a supermarket last
winter and grew it out this year. It seems to be reasonably early,
productive and healthy in my climate, and I wonder where it came from.
The bin at the store had other squashes labelled as coming from
Nicaragua and New Zealand, so this squash could have come from very far
away. Since I participate in seed exchanges, I'd like to acquire more
information if available.

(Btw, squashes cross (within species) very promiscuously and over
considerable distance, so if you want to save seed, you pretty much
have to hand pollinate, which means getting up before the bees and
taping closed the flowers that are about to open that day and waiting
until about 10am to perform the cross. You also have to contend with
bumblebees that will chew their way into your taped flowers. In my
climate, at least, cucurbits set a lot more fruit than the plant is
willing to grow to maturity, so you may have to do a lot of crosses to
get even a few fruits with good seeds. Squash aren't as bad as melons
this way, but if you have a short season, do the crosses as early as
possible, so you'll have plenty of chances. The latest set fruit are
most likely to abort, IME.

Paradoxically, the squash you buy in the supermarket probably come from
the middle of large fields of the same cultivar, so you are pretty sure
to get trueness to type from a squash you buy. Except for some of the
pepo squashes, e.g. acorn crossed with zucchini or ornamental gourds,
you'll likely get something as edible as its seed parent, so go for
it. Be adventurous. Enjoy genetic diversity and grow funny looking
vegetables!)