Contrasting Echinopsis flowers

[Phil_SK]

This time last year, I posted pictures of my old Echinopsis mamillosa, flowering for the first time. This year’s flowering has coincided with that of one of Bob’s plants, an E. leucantha. I’d read a fair bit about this species and knew that the flower structure is different to other Echinopsis in a number of ways. As I wanted some better photos of the beautiful E. mamillosa flower I decided to take several of each plant to show these differences.

The buds begin fairly similarly shaped (E. leucantha, first; E. mamillosa, second).

As the E. leucantha bud began to open, its unusual shape became apparent – the petals were folding out abruptly from the flower tube and are quite short.

After the flowers had fully opened, the very flat E. leucantha flower contrasts noticeably with the funnel-shaped E. mamillosa.

Viewed from above, the E. leucantha petals reflex slightly, something I’d not seen in Echinopsis s.s. before.

This brings the stamens into clear view. And there’s quite a difference in these, too. E. mamillosa, like other Echinopsis s.s. and Trichocereus types, has a circle of filaments joined at the point where the petals join the flower tube, and the others join to the inside of the tube along its length but are mostly fixed to one side. This results in a lop-sided arrangement, with the stamens generally grouped towards the bottom of the flower.

In E. leucantha, the stamens are arranged more symmetrically (as in Lobivia) and not just because the flower is held more vertically. There is seemingly no distinction of having two sets of stamens – just a tube densely packed with them on all sides.

Viewed from the perspective of other Echinopsis, E. leucantha is certainly a strange flower and it’s understandable why it’s seen by some as a bit of an oddity.

And I finally got a pic of my E. mamillosa that I was happy with.

[Bill in SC]

You know how I am about Echinopsis, Phil! I appreciate the pics!
Bill in SC

[Marlon Machado]

That is indeed quite interesting, Phil! I am sure when somebody finally investigates the relationships within Echinopsis sensu lato using DNA, then many of the questions we have today will be clarified, and I am sure some of the old groupings will be confirmed, while many previously unsuspected groupings will be revealed! I wonder where Echinopsis leucantha will end up being placed.

Cheers,

Marlon.

[Bill in SC]

I've never seen a plant with two sets of stigmas. Most interesting!
Bill in SC

[Mike]

Many thanks for posting all those pics. Fascinating. I wonder on what grounds E. leucantha was placed in Echinopsis in the first place...?!
Mike

[Phil_SK]

I wonder on what grounds E. leucantha was placed in Echinopsis in the first place...?!

Well, it's roundish (when young), terrestrial, ribbed and has long white flowers.

Bill - not two stigmas, two types of stamen (anther + filament). I've sliced the flowers to show what I mean a bit better. In the mamillosa you can see there's a central bunch of stamens that come from deep in the tube and another set that, whilst they do come from deep down too, they are joined to the sides of the flower tube up until the petals unlike the free central bunch. In leucantha you can see that the filaments are joined to the tube for part of their length but break free at different points up the tube, rather than all together at the rim. Because the free parts are all of roughlt the same length you get the 'forest of anthers' effect.

[Ray_in_Norfolk]

Lovely pics, Phil. My favourite genus!

E. klingeriana also has a similar arrangement of stamens although different shaped petals and the flower is held horizontally

[attachment 12921 klingeriana.jpg]

[Bill in SC]

Nice pics and thanks for the explanation, Phil!
Bill in SC

[Phil_SK]

Time for an update, I think.

The year after this the two plants flowered at the same time. I crossed them and sowed the seed. My records show it germinated well but I only have one plant and I can't tell whether I killed the rest by accident or if they were culled. I think the hybrid has flowered before but if it has I've not taken much notice of it until yesterday. To reduce the risk of my greenhouse overheating, there are a load of things slung over the roof to block the sun. Above this plant it's something quite solid, so when I went for a look round yesterday morning it was illuminated only by the low sun coming through the sides of the greenhouse, with attractive consequences that caught my eye.

Looking at the plant more closely, it shows characters somewhere between the parents - the body is pale green (mamillosa) with a hint of upswept spines (leucantha). The flower tubes is almost straight (leucantha) and opens to halfway between those of its parents. The filaments are inserted into the tube much as in mamillosa maybe a bit further up at the bottom of the tube.

As Marlon foresaw, a genetic study later indicated that Echinopsis leucantha isn't really an Echinopsis (Schlumpberger & Renner, 2012) and also that Echinopsis mamillosa isn't really an Echinopsis either - the combinations Acanthocalycium leucanthum and Lobivia mamillosa were published by Schlumpberger later the same year. I'm struggling to find a published name along the lines of ×Acanthobivia or ×Lobilcium.

I rather like the flowers; they are unusual enough for me to want to keep this plant.

[el48tel]

I agree .... a lovely looking plant