Search found 16 matches

by Detlev
Sat Mar 30, 2019 9:09 pm
Forum: Monthly Photo Competitions
Topic: March 2019 - Patterns
Replies: 22
Views: 4895

Re: March 2019 - Patterns

Ali Baba wrote:
Sat Mar 09, 2019 12:33 pm
Monanthes polyphylla
A wonderful picture that clearly fits the theme of "beautiful mathematical forms". The picture reminds me of the Brassica variety 'Romanesco', whose fractal patterns every mathematician should enjoy.
by Detlev
Sat Mar 30, 2019 9:05 pm
Forum: Monthly Photo Competitions
Topic: March 2019 - Patterns
Replies: 22
Views: 4895

Re: March 2019 - Patterns

NickHitchcock wrote:
Mon Mar 25, 2019 10:12 pm
Detlev they are brilliant photos, did you stack and stitch them yourself?
Yes, I made the photos myself with the focus stacking method. I'm glad you like the pictures.
by Detlev
Thu Mar 21, 2019 7:19 pm
Forum: Monthly Photo Competitions
Topic: March 2019 - Patterns
Replies: 22
Views: 4895

Re: March 2019 - Patterns

Here are some pictures -- perhaps less mathematical, but clearly patterns! So that no one has to puzzle: these are seed surfaces of cactus seeds. Escobaria vivipara Escobaria__vivipara.jpg Ancistrocactus uncinatus Ancistrocactus_uncinatus.jpg Stenocactus lloydii Stenocactus_lloydii.jpg Pilosocereus ...
by Detlev
Mon Dec 10, 2018 6:52 am
Forum: The Cactus & Succulent Plant Forum
Topic: (Another!) Gymno ID
Replies: 2
Views: 560

Re: (Another!) Gymno ID

Ralph Martin is right. The plant belongs to that group (Gymnocalycium subgenus Muscosemineum). It is a form of G. anisitsii (or G. damsii if you prefer). It is not G. friedrichii or G. mihanovichii. It is not easy to describe how to identify them. It is the flower and the stem (ribs, spination), but...
by Detlev
Fri Dec 07, 2018 9:52 pm
Forum: The Cactus & Succulent Plant Forum
Topic: Gymno ID
Replies: 6
Views: 1019

Re: Gymno ID

G. achirasense is closely related to G. horridispinum, and it is classified by some authors as a subspecies = G. horridispinum subsp. achirasense (and I agree).
by Detlev
Thu Dec 06, 2018 6:22 pm
Forum: The Cactus & Succulent Plant Forum
Topic: Gymno ID
Replies: 6
Views: 1019

Re: Gymno ID

The rough spination speaks for Gymnocalycium horridispinum. It is not G. marsoneri.
by Detlev
Sun Jul 08, 2018 9:20 pm
Forum: The Cactus & Succulent Plant Forum
Topic: Disappointed
Replies: 12
Views: 1968

Re: Disappointed

As already written here by other forum members, Gymnocalycium monvillei is very variable and can have pure white flowers, but also those with pink hue. With its green bodies, bright yellow thorns and large flowers, it is one of the most beautiful Gymnocalycium species in nature and cultivation. The ...
by Detlev
Thu Feb 11, 2016 2:34 pm
Forum: The Cactus & Succulent Plant Forum
Topic: Cactus botany books
Replies: 16
Views: 1811

Re: Cactus botany books

If you really want a technical book on the botany of cacti, I agree with Tony R: the "Cactus primer" of Gibson & Nobel is the best one available! I would recommend also "Cacti: Biology and Uses" of Park S. Nobel. ISBN 978-0520231573. When you have deeper interest in ecology and physiology, look for ...
by Detlev
Thu Jan 29, 2015 4:59 pm
Forum: Monthly Photo Competitions
Topic: January 2015, Transparencies
Replies: 8
Views: 3601

Re: January 2015, Transparencies

Not a transparent plant, but I like to add this photo here: It shows a seed of Astrophytum coahuilense, the deeply impressed hilum region covered by a thin, more or less transparent membran, which is already partly ruptured.
Astrophytum coahuilense.jpg
by Detlev
Sun Jan 11, 2015 2:45 pm
Forum: The Cactus & Succulent Plant Forum
Topic: Cactus Identifying
Replies: 16
Views: 2702

Re: Cactus Identifying

I would agree with anders:
4 = Mammillaria bombycina
8 = Gymnocalycium anisitsii/damsii

12 = Gymnocalycium uebelmannianum