Tag Archives: botany

Exobasidium ferrugineae

I found this fleshy, flower-like structure growing on Lyonia ferruginea (rusty staggerbush) at Archbold Biological Station (Venus, Florida). Heaths don’t make flowers like this, so I originally thought it might be an insect gall or phytoplasma infection, but I was wrong. After poking around online I think it’s Exobasidium ferrugineae, a Basidiomycetes fungus. Members of the genus grow in between cells of flower and leaf tissue, then in the Spring send hymenial tissue through stomata and other cracks in the epidermis, eventually turning the surface white with spores. I’d never heard of such fungi before. I’ve led a sheltered life.

Colin Purrington Photography: Fungi &emdash; Exobasidium ferruginea on rusty staggerbush (Lyonia ferruginea)

The above was the largest structure I found (perhaps 3 inches high) but there were dozens of others (see below) at the same location. If you’d like to know more about the species and genus, a good starting point is Kennedy et al. 2012 and references therein. In older literature the fungus was known as Exobasidium vaccinii (Burt 1915), but it seems likely that that species is host specific to Vaccinium vitis-idaea.

Theobroma cacao flower

Here are some close-ups of Theobroma cacao flowers at Longwood Gardens in Kennett Square. The plant is economically important (because chocolate) so people fuss over pollination a lot, but its bizarre floral anatomy is noteworthy regardless of the species’ value. The catchiest structures are the pointy red staminodes, stamens that became neutered over evolutionary time, which probably have roles in visual attraction of pollinators (ceratopogonid midges) and in preventing self pollination. The real stamens are enclosed in translucent petal pouches, though I chose to photograph this flower because one of the anthers has popped out.

Colin Purrington Photography: Plants &emdash; Theobroma cacao flower

According to one scenario I read, the flies first land on the exterior of the pouch, then crawl inside to lap up nectar from minute glands on the adaxial surface near the anthers. During their foraging they get coated with pollen, and some of the pollen gets deposited on the style (small white structure encircled by the staminodes) when they exit the pouch. Here’s a close-up that shows the translucent pouches:

Theobroma cacao anther sacs

Presumably some of transferred pollen is from previous visits at different trees (because most types are self-incompatible). These flies do such a terrible job pollinating that farmers often just do it themselves with paintbrushes and forceps. There’s even speculation that the domestication of T. cacao some 1500 years ago slowly changed the plant enough that the original pollinator(s) (bees?) were lost, with the midges being the only insects still interested in the meager nectar rewards.

The photograph below shows the cauliflory habit of the flowers, and the “parallel staminodes” variant of the flower.

Colin Purrington Photography: Plants &emdash; Theobroma cacao flower

Ellen’s monologue on sweet potatoes and yams

Ellen explaining difference between sweet potatoes and yams[#yamgate] For those people fascinated by the confusion some Americans have about sweet potatoes and yams, you should probably watch this clip from The Ellen Show.

ellen-sweet-potato-1

Ellen said this was a sweet potato.

During the monologue she showed two photographs: a white-skinned sweet potato (which she called a sweet potato) and an orange-skinned sweet potato (which she said was a yam).  That’s basically her joke: for all of you who thought the orange-fleshed tuber was a sweet potato, you have been misled … it’s a yam! Her implication was that the second photograph (orange tuber) was some sort of plant completely unrelated to a sweet potato.

ellen-sweet-potato-2

Ellen said this was a yam.

Of course, the monologue is really funny even if you know she’s wrong, and I’m sure she’s was just feigning ignorance (she’s brilliant at that).  But when I first heard the monologue, I thought to myself: wow, I wonder whether she’s from Louisiana?? Only somebody from that state would pitch the information in the way she did, I thought. So I Googled her and found her Wikipedia entry … she is.

Louisiana is the state that is actually responsible for the sweet potato / yam confusion. In the 1930s, a sweet potato researcher, Dr Julian Miller, decided that Louisiana could make a lot more money if it started marketing sweet potatoes under the name “yams.” Although nobody really likes to bring it up, “yam” is the word enslaved Africans used for the sweet potatoes, which they were introduced to in the Americas (sweet potatoes resembled the yams they ate in Africa). So Louisiana used that historical fact as a marketing scheme for selling a variety of orange-fleshed sweet potatoes. It really was brilliant, and the guy is a state hero.

Being the swell guy that I am, I’ve offered to send Ellen a yam. It would be hilarious to have a cook on the show deep-fry batches of yams and sweet potatoes and hand them out to the audience. Both are sweet, starchy, and deep-fry nicely. Ellen said at the end of the monologue that when she gets information on sweet potatoes and yams, she’s going to share it, so I think she’s set herself up nicely for this. So far, though, no word from Ellen about whether she would like a yam.

A photo of a yam is below, on right, just in case you’ve never seen one (likely). If you actually want to know more about yams (unlikely), please see my “Yams versus sweet potatoes” page.

Photograph of sweet potatoes and yam