Saturday, January 31, 2009

Winter in the Conservatory

Winter in the Conservatory
The American Desert House and especially the African Desert House at the Enid A. Haupt Conservatory are some of my favorite places, especially this time of the year. 
While a lot of plants are dormant in the new world, the old world is in bloom. Euphorbiaceae, Crassulaceae, Senecio spp., and most spectacular the Aloe spp., are showing their best colors now. It is strange to see these plants flower in January here in NY, exactly 6 month after staying in South Africa during peak Aloe-bloom-time. This is 'natural' behaviour nevertheless, as they obviously react to the temperatures and amount of light they are getting now. I am still not completely clear on how these two factors, combined with the amount of moisture available, really determine the plant cycles. I am also learning more and more about how much, or little, control there is in an artificial indoor environment.  
One thing this very clearly demonstrates is, that these African desert tropicals are from the south of the southern half of the globe. I love how horticulture and botany tie in with geography!

    Cotyledon tomentosa, Crassulaceae


I did not even notice when I took the following two pictures, but they are a wonderful example illustrating convergent evolution
All Agave spp. are from the Americas, and all Aloe spp. originate in the African Continent. They belong to different families, and are not closely related. Equally arid conditions, and similar ecosystems resulted into almost identical physical appearance. Evolution is definitely one of the larger 'transmission gears' in the complex interactions of the natural world.

Aloe sp. Asphodelaceae, detail

Agave sp. Agavaceae, detail

Agave sp., unfolded leaf detail

The genus Crassula might have some of my favorite flowers, here you see a very typical example. Note how half the anthers'  pollensacs already releasing their pollen (white tips), and how the stigmas are still arranged in this neat onion shape (they will unfold and become receptive later to avoid self-pollination).
 Anther and Stamen diagramm

Crassula ovata, Crassulaceae


Tuesday, January 20, 2009