Tritonia dubia/Ixia pumilio

Mary Sue Ittner
Sun, 26 Apr 2009 22:20:36 PDT
Hi David,

Tritonia dubia.

Distribution: Eastern Cape Province, (Port Elizabeth and Uitenhage 
Districts) of South Africa.

Morphologically the species links Tritonia and Ixia. This is the only 
species of Tritonia with wholly actinomorphic flowers. It has the flower 
coloring typical of a Tritonias, salmon pink or orange pink with dark veins.

Flowers:  a widely cup-shaped and later almost salver shaped perianth, and 
erect, centrally placed stamens and style. Bracts to 10 mm long (no color 
mentioned.) Leaves are 5 to 8, suberect or spreading, lanceolate-ensiform 
100-160 x 3-8 mm. Capsules are elongated ellipsoid, more or less 25 mm. 
long.  Flowers July to September. There is a figure in the Flora of 
Southern Africa, Ixioideae. Perhaps I can get Bob to scan it for me and 
send it to you privately.

Ixia pumilio is described as old rose with conspicuous darker median veins. 
It is known only from its type locality, the banks of Breed River south of 
Worcester where it grows in deep sand. It flowers late August to September. 
Leaves are 3 or 4, linear, 2 to 5 mm. wide, loosely twisted, bracts opaque, 
light brown with dark veins. There is a figure of it in Goldblatt, P. & 
Snijman, D. 1985. New species and notes on the southern African genus Ixia 
L. (Iridaceae). South African Journal of Botany 51: 66-70. This is not a 
reference I have a copy of.

Since there are no pictures or drawings in any of my books of Ixia pumilio, 
I can't compare the two visually, but the Ixia monograph says it is closely 
allied to Ixia latifolia, mostly differing in its flower color. Here is 
Bill Richardson's description of it.…

And Dash's picture:

I've struggled over this one a lot  and the pictures of both on the 
Internet are very similar. I have decided that my plants were really 
Tritonia dubia. And since one of the ways to tell Ixias from Tritonias is 
that Ixias are actinomorphic and Tritionias zygomorophic, but T. dubia is 
the former, it makes it even more difficult. T. dubia does not have 
sclerenchyma strands in the leaf margins which is a characteristic of 
Ixias. I have no idea what that means, but if you do perhaps that will 
help. Your description of the size of the leaves and the color of the 
bracts may be helpful. Alberto's description of how to tell the two genera 
apart (Ixias grouped on the end of the stem and Tritionia more spread along 
the stem) may be helpful too, but a few Ixias I have seen and grown are 
also spread along the stem. Stamens are described as symmetrically disposed 
in Ixia and irregularly disposed, often curved towards upper lobe in 
Tritonia, but it isn't clear in the description of T. dubia that this is 
true for this species (centrally placed stamens and style).

I hope this has helped.

Mary Sue 

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