Sunday, March 21, 2010

Acharagma roseana – flowers and fruits

To be honest, Acharagma roseana plants are not particularly ingratiating – the flowers are not breathtaking nor is the spination stunning. To me, the attraction of A. roseana lies in its close relationship with Lophophora and Obregonia, making it an obvious candidate for hybridization experiments.

Acharagma roseana flower with pale yellowish tepals with brownish pink midveins
Acharagma roseana flower with pale yellowish tepals with brownish pink midveins

Gene sequence studies by Butterworth et al. (2002) suggest that Acharagma belongs in a well-supported taxonomic clade with Lophophora and Obregonia. They sum up their results as follows:

LOPHOPHORA CLADE. Although there is strong support for this clade (87% bootstrap, 5 decay steps), few morphological features unite this clade. All members have napiform or carrotlike tap-root systems, although these features are also found in other members of the tribe.

The two species of Acharagma have been a source of taxonomic confusion. […] The rpl16 intron data suggest the removal of these two species from Escobaria, placing them in a well-supported (bootstrap 87%, decay 5) clade containing Obregonia and Lophophora, the latter shown to be polyphyletic based on this topology.

(the closing remark on Lophophora being polyphyletic is an interesting statement in its own right, but that’s a whole other story)

Acharagma roseana flower with pink tepals with darker red-tinged midstripe
Acharagma roseana flower with pink tepals with darker red-tinged midstripe

In The New Cactus Lexicon, Hunt describes this species as Acharagma roseanum - I’m not sufficiently well-versed in the Latin language to say which form of the name is correct, but according to this site on botanical Latin the specific epithet must match the genus name in gender. As Acharagma is from the Greek a, without, charagma, groove (the gender of which, according to Hunt, is neuter) this would warrant the “-um” ending. I’m a firm believer in applied laziness so I’ll stick to the (apparently erroneous) “-a” ending for a wee bit longer and avoid having to re-label my plants ;-) Hunt accepts two subspecies: ssp. roseanum and ssp. galeanense, the latter having more spines and slightly larger, cylindrical bodies, compared to the egg-shaped body of the typical form.

Comparison of the two different color forms of Acharagma roseana flowers
Comparison of the two different color forms of Acharagma roseana flowers

The Acharagma roseana plants featured in this post were started from seed in 2005 and flowered freely last summer. As mentioned I would like to use these plants for hybridization experiments with Lophophora but I still need to come up with a good protocol for avoiding self-pollination. The locality information for these specific plants is: LX 578; Ramon Arizpe, Coahuila - “Ramon” should probably read “Ramos” but I'll stick to the information from the vendor’s seed list.

Acharagma roseana with fruits
Acharagma roseana with fruits

Like most other parts of Acharagma roseana the fruits are not showy either. They are an inconspicuous yellowish green color, but have a surprising, not unpleasant, tart taste reminiscent of gooseberries.

The plants grow in my unheated greenhouse and I hope they survive the month long cold snap that is just now loosening its grip of Denmark.

Monday, March 15, 2010

Echinocereus engelmannii v. armatus - flower and fruit

My Echinocereus engelmannii v. armatus (Joshua Tree National Park, California) flowered for the first time in the late spring of ‘09.

Echinocereus engelmannii v. armatus flower, close-up
Echinocereus engelmannii v. armatus flower, close-up

The flower was beautiful with bright yellow anthers, a mesmerizing green stigma, and petals ranging from intensive pink to almost crimson at the center of the flower.

Flowering Echinocereus engelmannii v. armatus
Flowering Echinocereus engelmannii v. armatus

The plant easily lives up to its varietal name - even the flower stalk is heavily armed with spines, protecting the ovary and the coming fruit.

Echinocereus engelmannii v. armatus flower armed with spines
Echinocereus engelmannii v. armatus flower armed with spines

I hand-pollinated the flower and two months later the plant bore fruit. This is the only mature Echinocereus engelmannii v. armatus in my collection and no other Echinocereus plants flowered at the time so my E. engelmannii v. armatus seems to be self-fertile. Time will tell if the seeds are viable.

Echinocereus engelmannii v. armatus with fruit
Echinocereus engelmannii v. armatus with fruit

Echinocereus engelmannii v. armatus with fruit, top view
Echinocereus engelmannii v. armatus with fruit, top view

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