Redbelly snake again

photo of a coiled redbelly snake
Storeria occipitomaculata

Last July, we found a dead redbelly snake (Storeria occipitomaculata) on our driveway, but we couldn’t be sure if it was resident on our property or had been dropped by a bird. This morning, my wife found a live one crossing one of our garden paths. What I find most interesting is that Dekay’s brown snakes (Storeria dekayi) are very common on our property, so we apparently have both Storeria species sharing the same habitat. Eastern worm snakes (Carphophis amoenus) and smooth earth snakes (Virginia valeriae) live here too, and all four of the little snake species have similar diets. Worm snakes are obviously specialized for burrowing and preying on earthworms, but the other three species inhabit the leaf litter and hunt a wider range of prey. According to Palmer and Braswell [1] earth snakes eat earthworms, insects, and snails, while redbelly and brown snakes prefer slugs and snails (with some earthworms). So the question is, are these little snakes directly competing, or do they inhabit subtly different microhabitats that are not obvious simply by looking at dietary preferences?

(A fifth small snake species, the ringneck snake (Diadophis punctatus) also lives here, but its diet includes small amphibians and lizards, so I think it is less likely to compete with the other species).

Reference

Palmer, W.M., and Braswell, A.L., 1995, Reptiles of North Carolina, University of North Carolina Press.

Photo of a redbelly snake showing its orange belly

Another photo of a redbelly snake

…And a copperhead

Last weekend, my wife and my niece were collecting rotting logs to line the bottom of a very large planter–sort of micro-scale h├╝gelkultur–when my niece uncovered this snake in our old log pile. My sister has been teaching her to identify venomous snakes, so she simply said “hello copperhead” and stepped back. The snake posed nicely while we took photos, and then slowly retreated deeper into the log pile. We decided that we had enough logs for the planter.

photo of a coiled copperhead
Agkistrodon contortrix, eastern copperhead

Mauve Sleekwort

Liparis_lilifolia
A not-very-good photo of Liparis lilifolia. Its brownish flowers are difficult to spot in the leaf litter and even harder to photograph satisfactorily.

After sixteen years, I thought I had found all of the interesting plant species growing on our property, so I was very surprised to stumble across a flowering specimen of Liparis lilifolia yesterday evening. This species is known as the lily-leaved twayblade orchid, but I prefer its alternative common name, mauve sleekwort.

L. lilifolia grows at scattered locations throughout the mountains, piedmont, and coastal plain of North Carolina, and its range extends over much of eastern North America, from Quebec and Ontario south to Georgia. Its flowers are visited by flies, although they are not pollinated very frequently. Coincidentally, one of my neighbors had emailed earlier in the week to say she had found the species on her property, so today we served as orchid matchmakers and attempted cross-pollination with toothpicks.

My plant is growing in the woods outside our deer fence, so I have covered it with a wire cage while we wait to see if viable seed will be produced. And now, I’m wondering what else I have overlooked in the leaf litter.

Premature cicada

Magicicada1
A periodical cicada from Brood XIX

While walking down the garden path on Friday, I was surprised to see a red-eyed insect sheltering from the rain on an onion stem. The periodical cicadas (Magicicada species) around here are part of Brood XIX, a thirteen-year brood which isn’t due to emerge until spring 2024. This one is a year early.

If that makes absolutely no sense to you, allow me to tell you about one of the most interesting insects in North America. Most gardeners are familiar with the big annual cicadas (Neotibicen species) which emerge from the ground every summer, leaving their empty nymph exoskeletons clinging to tree trunks before retreating to the canopy to call loudly. The life-cycle of these cicadas spans several years underground, but some proportion of the population matures and emerges every year–hence annual cicada. (Incidentally, cicadas call during the day–a lot of people misidentify the nocturnal calls of katydids, thinking they are produced by cicadas.)

Periodical cicadas, readily identified by their slightly smaller size and startling red eyes, are less familiar or perhaps more likely forgotten between emergences. They emerge en masse on a specific schedule that depends on species: some have a seventeen-year lifecycle and others a thirteen-year cycle, but the specifics of how the internal clock is generated are unknown [1]. The insects are divided into broods, depending on the particular calendar dates of their emergence, and a brood may contain several species with the same cycle-length. For instance, Brood X consists of three 17-year species and is expected to emerge in 2038. The same species are found in Brood V which will emerge in 2033. It is all very complicated.

Synchronized mass emergence presumably overwhelms predators and increases the percentage of cicadas that survive to mate. “Stragglers” that emerge early or late are doubly disadvantaged–they are more likely to be eaten and less likely to find a mate. New broods are thought to be formed on rare occasions when large numbers of stragglers emerge together and overcome those disadvantages.

Another periodical cicada photo
Magicicada tredecim straggler seen on Saturday

On Saturday, I spotted another straggler on the other side of the house. A quick search of iNaturalist shows a cluster of straggler observations in our part of NC from last year, and we seem to be on the way to repeating it this year–not sure if that means there are a lot of stragglers emerging or a lot of biology geeks living in the Research Triangle or both. In any case, I and others locally are looking forward to the mass emergence next year.

Here’s my favorite photo from the last emergence in 2011:

DSCN1564
Newly metamorphosed Magicicada and shed nymph exoskeleton (2011)

Reference and further reading

1. Sota, T. (2022). Life-cycle control of 13- and 17-year periodical cicadas: a hypothesis and its implication in the evolutionary process. Ecological Research. 37:686-700.

Hillia triflora and the bird pollination syndrome

photo of Hillia triflora flowers
Hillia triflora flowers in the typical cluster of three at the end of a branch

Hillia triflora is a somewhat obscure epiphytic shrub in the coffee family, Rubiaceae. I didn’t know it existed until I ran across a small cutting for sale on eBay a few years ago, and after a quick google search, I made certain that I would be the high bidder when the auction ended. It’s a hummingbird-pollinated plant, and as I have noted before, this gardener is attracted to the same floral features that attract hummingbirds.

H. triflora comes from central America, with specimens collected from southern Mexico to Colombia, and although it usually grows at higher elevations, plants have been found at only 100 m above sea level in Costa Rica [1]. As might be expected from this wide geographical and altitudinal range, the plant seems to be quite tolerant of both summer heat outdoors and cool winter nights in the greenhouse. There are two subspecies with overlapping range, H. triflora subsp. triflora, and H. triflora subsp. pittieri; judging by the equally sized leaves on flowering shoots and narrow, uninflated flowers, my plant belongs to the nominate subspecies [1].

The growth habit of this plant is very interesting. It forms an open shrub with flexible, infrequently branched stems bearing opposite, semi-succulent leaves. Each stem terminates with a protective sheath. Over the course of a couple of months, the sheath slowly swells and eventually splits, revealing that it was formed by a pair of bracts tightly pressed together. Emerging from the sheath is either a new stem segment with a pair of leaves and new sheath, or a cluster of (usually three) flower buds. At the base of the flower buds is one or more new sheaths, so the stem sometimes branches after flowering.

photo of the sheath at the end of the branch
Sheath at the end of a branch. At this stage in its development, it is difficult to see that it is composed of two bracts.

The roots of H. triflora are fibrous, without obvious adaptations to epiphytic life, and plants in habitat are occasionally found growing terrestrially in leaf mould or rotting wood [1]. Consequently, I added some coarse peat to the mix of orchiata bark and perlite in which I potted my plant. I water when the mix is almost dry, and so far the plant seems happy. It grows with my vireyas under shade cloth in summer and goes back in the greenhouse when temperatures drop below 50 F (10 C) at night.

The flowers of H. triflora are very similar to those of the unrelated coral honeysuckle, Lonicera sempervirens (Caprifoliaceae), that grows wild in the woods around my house–it’s a remarkable case of convergent evolution driven by birds. I would guess that the hummingbird responsible for pollinating H. triflora is roughly the same size as the ruby-throated hummingbirds (Archilochus colubris) which pollinate L. sempervirens. I suppose it is even possible that A. colubris is a pollinator of H. triflora, given that the birds over-winter in central America and H. triflora has flowers in November/December as well as March-May [1].

photo of coral honeysuckle flowers
Lonicera sempervirens flowering at the edge of our woods today

comparison of L. sempervirens and H. triflora flowers
Lonicera sempervirens (top) and Hillia triflora (bottom)

I have previously featured a variety of hummingbird pollinated flowers on this blog, both native plants (Aquilegia canadensis, Aesculus pavia, Lobelia cardinalis, Lonicera sempervirens, Spigelia marilandica, Silene virginica) and tropicals (Juanulloa mexicana, Macleania sp. aff. smithiana, Macleania pentaptera, Ceratostema glans, Cavendishia capitulata, Bouvardia ternifolia, Bessera elegans, Behria tenuifolia, Columnea microcalyx, Columnea crassifolia). These flowers share obvious characteristics: bright red/orange/magenta color, tubular (or sometimes bell-like) shape, lack of fragrance, and copious nectar. The same features are seen in plants from Africa, Asia, and Australasia where there are no hummingbirds. In those locations, sunbirds (Nectariniidae) and honeyeaters (Meliphagidae) fill much the same ecological niche. However, because sunbirds and honeyeaters are less likely to hover than hummingbirds, bird-pollinated flowers in the old world are usually not pendant and are often attached to a stout inflorescence that allows the birds to perch (see, for example, Cyrtanthus obliquus).

photo of flowering Dermatobotrys saundersii
Dermatobotrys saundersii is an epiphytic shrublet from South Africa that is likely pollinated by sunbirds. It is easy to grow from seed but seems not to like hot North Carolina summers. I have been unable to keep plants going for more than a couple of years.

flowers of Dendrobium chrysopterum
The flowers of Dendrobium chrysopterum from New Guinea bear all the hallmarks of bird pollination. Like similar Dendrobium orchids, they may be visited by honeyeaters.

Reference

  1. Taylor, CM (1989). A revision of Hillia subg. Ravnia (Rubiaceae: Cinchonioideae). Selbyana 11: 26-34.

Six on Saturday #74 (April 22, 2023)

Happy Earth Day! This would be an obvious day for working in the garden, but unfortunately we will have thunderstorms rolling through for most of the day (though luckily the potential for tornadoes seems to be southeast of our location). Here are a few pictures taken this morning before the rain, rounded out with a couple taken earlier this week.

1. Paeonia ‘America’

Photo of Peaonia 'America' flower

I planted this herbaceous peony about three years ago. It produced its first buds last year, but they all froze and aborted. This year, two buds survived, and I finally have the first flower. Each day, the flower starts to open after I leave for work and closes before I get home, so it was tricky to get a photo. The flower is already closing in this picture, and I only saw it partially open because I left work early to catch eldest offspring’s last high school tennis match.

2. Paeonia obovata (Japanese woodland peony)

photo of white Paeonia obovata flower

This peony does well the shade under a dogwood, where it grows among trilliums and Calanthe orchids. The white-flowered form sometimes goes by Paeonia japonica, but Kew lists that name as a synonum of P. obovata.

3. Calycanthus floridus (eastern sweetshrub, Carolina allspice)

Photo of Calycanthus floridus flowers and leaves

This native woodland shrub is famed for its fragrance, which is often compared to fresh strawberries. My plant smells more like overripe fruit–not horrible, but not something I’d seek out. If buying one to grow close to the house, it’s probably best to shop for plants in flower and give them a sniff test before laying down your money.

4. Actias luna (luna moth)

Luna moth with damaged wings

Luna moths only live for a few days after completing metamorphosis, and this one was at the end of its lifespan. It could no longer fly, and was fluttering weakly across the lawn this morning.

5. Quercus phellos (willow oak) growing on Juniperus virginiana (eastern red cedar)

photo of willow oak growing from the trunk of a red cedar tree

Not in my garden, but local, are two of my favorite individual trees. The pale green leaves are a small willow oak which is growing epiphytically on a red cedar. The oak must have grown from an acorn that fell or was deposited by a squirrel into a crack in the trunk of a red cedar. Enough water and organic debris sifts down to keep the oak alive, and I have been watching it grow slowly for almost a decade. Each spring, it’s always encouraging to see that the little oak has survived another year.

6. Allium schoenoprasum (chives)

IMG_0286

Garlic chives, Allium tuberosum, seem to be more vigorous in this climate, but this little clump of chives is doing fairly well. It’s in a raised bed shared with walking onions and garlic chives, which are permanent residents of the bed, and two varieties of garlic (softneck and hardneck), which will be harvested in June.

Jim at Garden Ruminations is the host of Six on Saturday. Head over there to see his Six for this week and find links to the blogs of other participants.