I bought a citrus mail order from a non specialist supplier, listed as a grapefruit......
They insist it is a grapefruit, but all the ones ive seen have a distinctive leaf, i have a few others and they are all the same leaf type, the fruit doesnt look like grapefruit either, to me it looks like a lemon of some type, its leaves and fruit match my lemon trees
The pictures are a bit yellow as taken with the growlights turned on.










My other grapefruits have this type of leaf totaly different from the other one that is claiming to be a grapefruit

Can you get a grapefruit with out this leaf, i think the tree is a lemon tree

It does not look like a lemon to me. Lemons have redish flower buds, the flower buds in your picture are pure white. Lemons petioles are not as winged as I see in your pictures. I think it is a small grapefruit. - Millet

the last photo is of my grapefruit that i know is a grapefruit, the others are the wierd grapefruit
the leaves seem to have no wing on the petiole visible maybe a hint of one on some leaves nothing like the last photo though , the flowers are pure white, one had a tiny bit of purple, all the rest pure white but no winged petiole at all

The bottom photo is a Grapefruit. The photos above are lemons. Grapefruit never have a nipple

I thought all 5 of the pictures were of the tree you suspected as being a lemon, including the last picture. - Millet

thanks,

i thought that must be the case, i reread my post and what i wrote isnt exactly clear!

If its a lemon,with no thorns at all , what variety would you guess it is? is there any way of telling?

Meyer lemons can have white to almost red blooms. Meyers can also be almost thornless.

Lisbon lemons have upright growing branches, which are usually thorny. The Eureka lemon is distinguished from the Lisbon as being a smaller size tree with spreading branches which are thornless. There are a lot of other lemon varieties. However, the vast majority of lemons grown are either a Lisbon or Eureka. - Millet

All the fruit fell off last year, it was repotted into a larger ( i think 40L ) pot , it is now very much larger, about 6 foot accross by 6 foot high bush, it was under the growlights on a heater mat all winter and has been outside since the end of march,
im sure it is a lemon tre in places.... but it was sold and labled as a grapefruit tree , well i was sure ....but everything is different from last year, it is the same tree!

The flowers last year were totaly white, now there tinged purple and the leaves are much larger and very ridged



The new growth is purple, like lemon tree ( different branch to the flowering/fruiting one this year, this branch with red new growth fruited last year ), the branch with purple fruit grows new growth green! purple growth is pointy, green growth is rounded at the ends



But last years green fruit,...... on this branch there not, they started off purple and stay purple, kind of lemon shaped, but not the same , they have a `funny end` on them , they were green ( on another branch ) last year without the funny bent end

the trunk is about 1.5 inch in diamiter and about 2 foot high, it is a trifoliata rootstock and stem, budded around the top to give it branches , im womdering if each branch on this tree is budded with a different variety, as only one branch is flowering so far this year, the one that flowered last year with white flowers is one of the others, or can a tree change this much over a year or is is a multi grafted dodgy tree

I think what you have is some type of citron.

I think most lemon leaves have a distinct odor, at least all of mine do, especially the young leaves.

StarLoc, red colouration is caused by different conditions. Now tree is standing outside, so the temperature's changes are higher (warm day, colder night). It provokes your citrus to produce red-coloured young leaves, fruits and purple flower buds. When your citrus was standing inside, day and night temperatures were almost identical, so the red colouration didn't reveal. Of course there are many varieties that never produces red-coloured new growths and flower buds, but your three isn't one of them.
And big leaves. They're larger because they have more sun and fertilizer. Especially nitrogen (N) causes large (sometimes too large) leaves.

Your plant is a lemon or a citron. I've got a grapefruit and it never produces red-coloured new growth. Tolumnia is right, lemon leaves have a distinct odor, but some citrons' leaves have that odor also. So it's very difficult to decide is it a lemon or a citron only by smelling it's leaves.

The leaves smell the same as my other lemon trees and also the same as budhhas hand as well, they dont smell like bears lime , orange or mandarin or kaffir lime

Half the tree has green new growth, and the other half red new growth, growing outside at the same time, , when i bought the tree it had been outside at a garden center and the frut was green, fruit grew during the winter , it was also green but the fruit was only on half of the tree, the other half was `more pruned
Looking closely today, half the main branches grow red new growth, half grow green new growth, non are shaped like a grapefruit as it has the large petiole wing

During the winter, the growing temperature was about 25-30C during the day, aprox 1000 watt of light (metal halide 600w) and (400w sodium) , root temperature set at 28F, night time temperatues drop to 12C or below every night, when the lights were off

i have a few lemon trees that were inside and one outside during the winter , all have red new growth, apart from this and one other, one other grows lemons, that start off green and turn yellow in the nornal way, this one there getting quite large now, for how long they have been there, they have grown rapidly

the flowers are quite large as well, about 1 inch long before they open, as soon as the petals drop the fruit is dark red/purple , i have no other citrus that has red fruit at this size

the tree deffinately isnt a eureka, lisbon, volkamerenia, meyer or pink variengated lemon , the fruit is totaly different shape and colour than all my other trees

Im guesing that Laaz is right and it has to be something like a citron, for this ranch at least!, its leaves on this branch are closest to my budhas hand trees, on this branch there almost the same size as my hand with very rounded ends and ridged , the other branches with the red new growth , pointy flatter leaves and green fruit have half size leaves of this branch

1) How do you know that the rootstock is a Poncirus?
(The question could seam silly because I don't know the level of your knowledges.)

2) If all the "new" branches come from the same point, it could be a bud mutation.

The rootstock keeps producing trifoliata shoots, around the top and bottom of the stem, they match exactly to my poncirustrifolata tree and seedlings, the leaf shape is a bit different to the citrange suckers i hve on other plants

A lot of the trees sold as ornamental citrus sold here no matter what the variety seem to be budded at the top of the stem/trunk, at the overall hight of the trunk, not at the bottom of the trunk like the commmercial citrus plantation trees that tend to be on citrange rootstock

you tend to get sprouts of rootstock from nearby the wanted variety branches on the trunk or on some of the similar trees the 1 inch trunk has split to 1/2 inch branches the branches are cut off and budded with the variety, these tend to grow more rootstock