Saucer Magnolias in march

Saucer Magnolia (Magnolia x soulangeana) outside of
Worrilow Hall at the University of Delaware

In the month when we would generally be expecting to see snowdrops and the earliest few daffodils flowering, we're instead greeted by cherries and magnolias in full bloom. The whole situation has me feeling a bit uneasy... maybe it's just that I grew up in New England, but I'm still fearing a late frost or snowstorm will decimate this premature spring landscape. A quick look at the extended forecast however shows no such thing, so maybe we're safe.
Were I still a full-time horticulturist, I'm sure I'd be feeling a further sense of panic as my busy season would be starting up far before I had planned, but now as a full-time student, maybe I can afford to take a relatively worry-free approach to the early arrival of the spring flora, and in particular my personal favorite, the magnolias.

My interest in the genus began the first time I saw Magnolia macrophylla, a native summer-flowering species I'll discuss on this blog a bit later. I didn't pay as much attention to the spring flowering species until doing a year-round internship at the Polly Hill Arboretum, where one of my projects involved recording the flowering status of the magnolia collection on a weekly basis.




I was surprised to see the Magnolias burst into full flower so quickly this year, as I usually notice a solid gap between the time when the Star Magnolias (Magnolia stellata) start, and when the Saucer Magnolias join them. Though Magnolia biondii entered bloom about when expected, I recall seeing a few Star Magnolias breaking bud, then when I checked again a few days later a good half of the UD Magnolia collection was approaching full bloom.
Though I certainly enjoy the Star Magnolias, I find their flowers a bit flimsy in comparison to those species flowering later in the season, with the Saucer Magnolia one of the first to begin the trend. Maybe it's the size of the flowers (sometimes reaching 10" in diameter), or the way the thickness of the petals give the flower a more "solid" appearance than much of what else is in bloom this time of year.

The Saucer Magnolia is actually a hybrid between two asian species, the Yulan Magnolia (Magnolia denudata) and the Lily Magnolia (Magnolia liliiflora). The Yulan Magnolia was long cultivated in asia for its pure white flowers, and the Lily Magnolia is a shrubbier species with pink flowers. The offspring has found a home in our landscape, as is probably one of the two more commonly planted and easily recognizable of the spring-flowering Magnolias (the other being the Star Magnolia).

Magnolia x soulangeana 'Sundew'

All the above images are of the standard hybrid, but I also witnessed the cultivar 'Sundew', which based on what I just read at the Magnolia Society's Cultivar Checklist, is an older cultivar which may possibly have some relationship to Magnolia cambellii. It also appears to be somewhat uncommon, or at least I would assume so based on it's notable absence from Dirr's Manual of Woody Landscape Plants and Callaway's The World of Magnolias.

Though Saucer Magnolias often struggle in less mild springs, with an early warm snap followed by a late frost almost certain to kill off the emerging flowers, when it does flower successfully, I find its firm, upright flowers a sign that spring has arrived, albeit surprisingly early in this case.

Took many pictures of magnolias on Saturday (with many more to come next week) so probably plenty more magnolia posts to come over the next few days. Next time I'll probably talk about Magnolia kobus and Magnolia x loebneri. Until then there's always plenty about Magnolias on the Magnolia Society's facebook page.

A few native pines

Though spring is rapidly approaching, with snowdrops and some of the earliest daffodils and crocuses already appearing (as well as flowering cherries and magnolias in some places), the canopy still looks noticeable sparse as our deciduous trees have yet to show signs of leafing out, the only green up high provided by either broadleaf evergreens such as the American Holly (Ilex opaca), or the needles of conifers such as the pines.

The evergreen nature, as well as their distinct needles make members of the Pine Family (Pinaceae) one of the easiest groups of trees for the less botanically inclined to identify: Pines have needles, other trees have leaves. The strength of this distinction holds well in plant taxonomy, as it is actually made at the phylum (or division) level, which as you remember is the second category after kingdom: this is indicative of the fact that Conifers and deciduous trees took a different evolutionary path quite a long time ago, with deciduous trees and other flowering plants or angiosperms branching off from the conifers sometime in the Cretaceous Period 65,000,000 to 145,000,000 years ago.

Regardless, needles are considered to be the leaves of the pine: they photosynthesize and have similar anatomy, they're simply round instead of flat, and have a tendency to stay on the tree for more than one year (2-5 is probably a good range). They also usually have a thick waxy cuticle that leaves of most deciduous trees lack.

Pines are distinguished from their relatives such as Spruces, Firs, and Hemlocks in that they have needles borne on the stem of a plant in groups of two or more in a structure called a fascicle, as opposed to being borne singly.

Small grove of Eastern White Pines (Pinus strobus) at the University of Delaware

Cone of Pinus strobus

The Eastern White Pine (Pinus strobus) can easily be distinguished from the other pines listed here as they have five needles per fascicle as opposed to two or three. The needles are also a good deal thinner, less prickly to the touch, and give the tree in general a much softer appearance, even when viewed from a distance. The tree usually reaches a height of 50-80 feet in height, and can also grow quite quickly, sometimes upwards of two feet a year. It is unfortunately very intolerant of pollution, making it quite difficult to grow in urban settings.

Pinus palustris (Longelaf Pine)

Longleaf Pine (Pinus palustris) is a more southern species, and quite easily identifiable due to the sheer length of its needles: they can approach upwards of a foot. There are some other pines which get as long or even longer, but in tropical, not temperate areas. The terminal bud on the stem is also a good ID characteristic, being large and white, though probably unnecessary given how distinct the leaves are.

The growth habit of Longleaf Pine is also somewhat interesting: for the first seven years of its life, it looks more or less like a grass, barely reaching a foot in height. It is however in the process of developing a root system, and once established, it rapidly increases in height, usually getting to about 60' but in some cases well over 100'. This growth habit actually makes the Longleaf Pine an undesirable plant for foresters, as the amount of time it spends in the "grass stage" makes it rather economically nonviable in terms of wood production.

Close up of the needles of Pinus palustris. Almost wish I had my hand in the frame for size comparison, but regardless, you'll know this species when you see it.

And in colder weather...

The next three pines are a bit less distinct: Pitch Pine (Pinus rigida), Pond Pine (Pinus serotina), and Loblolly Pine (Pinus taeda) all have either two or three needles per fascicle (usually three).  If you're in New England however, you're unlikely to see the latter two species as they don't really start appearing in the wild until you get to New Jersey and points south.

A young Pitch Pine (Pinus rigida) at my parents' house in West Tisbury, MA

Pinus rigida as a bonsai, seen
at the Philadelphia Flower Show

Pitch Pine (Pinus rigida) was one of the first trees I learned how to identify. When at summer camp one year (I cant remember if it or Sassafras came first), I remember the counselor talking about the three needles per bundle (I doubt the term "fascicle" was used), saying we could remember that since in baseball they throw pitches, and three strikes is an out. The only other pines I remember seeing on the Vineyard were Red Pine (Pinus resinosa) which only has two needles per fascicle, and Eastern White Pine (Pinus strobus), which as we already know has five, though maybe there were a few other two-needle pines as well. I'll have to ask about it next time I'm down there (well, actually "up" there now that I've moved to Delaware).

Pitch Pine is quite ubiquitous on the vineyard, especially around my parents house right now as most of the oaks have died following repeated attacks by the Forest Tent Caterpillar. opw the Pitch Pines have the sun they need and are rapidly taking over the property. I'm all for it personally but haven't been able to convince my dad to let them live: they're one of his most hated trees, and probably justifiably so as I seem to recall him needing to cut a rather mature specimen down right next to the house which had its own established Yellow Jacket population associated with it. Still, though the species is probably not the most ornamental of pines, it does do quite well in poor soils so it at leasts has its place in the wild.

Loblolly Pine (Pinus taeda)

Loblolly Pine (Pinus taeda) resembles Pitch Pine to a certain extent, though it does have a tendency to get a bit taller (upwards of 90' where Pitch Pine usually, but not always, maxes out around 60'), and as noted about Loblolly Pine isn't generally found in the wild up north. Most notably however, the needles of Loblolly Pine are a bit longer: between 6-10" as opposed to Pitch Pine's 3-5".

What Loblolly Pine really resembles, in both range and needle length is Pond Pine (Pinus serotina). There are two easy ways to tell them apart however. First, the cones of Loblolly Pine are quite a bit longer and more extended. Since cones are not always present however, you can also look at the terminal bud on the stem. In Pond Pine, the bud will be white and covered in resin, whereas in Loblolly Pine, it is not and is red in color.

The word "Loblolly", according to dictionary.com anyway, apparently refers to a mud pit with the consistency of porridge. Who knew?

Shorter and rounder cones of Pond Pine (Pinus serotina)

Longer cones of Loblolly Pine (Pinus taeda)

White, resin covered bud of Pond Pine (Pinus serotina)

Redder terminal bud of Loblolly Pine (Pinus taeda), you want to look at the structure on
the end of the stem: try not to be distracted by the developing male cones underneath.

Pond Pine (Pinus serotina)

Not much more to say about Pond Pine (Pinus serotina). It's a close relative of Pitch Pine with a more southern range. It also tends to inhabit a wetter habitat, as it's common name would suggest, generally found in areas with wet, poorly drained soils. Such as in the proximity of pines.

Out of the five pines discussed here, only one of them, Eastern White Pine, is really popular as a landscape plant. Though Pitch, Pond, and Loblolly Pine probably aren't the most ornamental and interesting of trees, I find it surprising that Longleaf Pine isn't more popular due to the needle length. I suspect that the same production issues which bar it from use in timber production may be to blame, with nurserymen perhaps unwilling to dedicate greenhouse space to a plant which won't be of a decent size until almost seven years. Still, I think it's a neat pine I'll be keeping an eye out for in the future.


Not really sure what to talk about next... waiting on some of the Maple and Oak ID posts until I can get some leaf photos. I want to talk a little bit about algae but need to read up on that first, but I do have a few photos of trees with interesting bark it might be fun to discuss as well...

The Jungle: Orchids and their velamen

Wall of Orchids at Longwood Gardens, displaying some of the diversity

The orchid family is one of the most diverse groups of flowering plants, essentially in a tie for first with the asters. They can roughly be split into two groups based on their growth habit: the terrestrial, or those that live in the ground, and the epiphytic: those that live aerially, often planting themselves in the crotches of branches of canopy trees within the jungle.

Paphiopedilum, a terrestrial orchid

The Jungle was the second biome featured in the Living Planet, and one I found particularly interesting as it depicts a compound ecosystem consisting of three distinct "stacked" habitats where an organism might live: the forest floor, the trunks of trees, or the canopy of these trees. The epiphytic orchids reside in this second layer: not planted in the ground as we tend to think of plants as always being, and not tall enough to have unrestricted access to the sun.

Due to their choice of habitat, the Orchids can't rely on ground water, so must instead draw water from the air of the humid environment around them. In order to accomplish this, they have modified roots, some of which are actually aerial, white or silvery-grey in color, and spongy in texture.  This color and texture results from a covering of velamen, actually the modified epidermis of the root which helps to absorb and hold in water.

An Aerial root on a Phalaenopsis I've acquired

These specialized roots are what often serve as a source of difficulty when many try to grow these in their homes. They assume that due to their native habitat the plant needs a lot of water, and overwater the plant resulting in these roots rotting. They do like this humid environment (some orchids actually wiliting as soon as they're removed from 70-80% humidity), but can't stand having their "feet wet", so to speak.

Probably the most common type of orchid grown, and probably the easiest as well, is the Phalaenopsis, or the Moth Orchid. The common name comes from the floweres, but I feel saying they resemble moths is an understatement. When I first had the opportunity to look at one of these flowers close up, I was taken aback by how accurate this mimicry seems to be, with the center of the flower so approximating the head and eyes of the insect.

Eye to eye, or rather eye column to with a Phalaenopsis

Aggregate of several Phalaenopsis at Longwood Gardens

Last time my Phalaenopsis flowered, I was curious enough to lift up the "moth face" (which is considered the "column" of the flower), curious as to what was underneath. Immediately upon lifting it up, two anther sacs popped out from underneath, exposing the reproductive parts of the flower. This stigma is further below in this structure. The pollinator would inadvertently lift up the "face" or cap of the column when inside the flower, then be covered with the pollen from the anthers, which would be deposited into the stigma when they do the same with another Phalaenopsis flower.

I wish I could show some detailed photos of the column, but couldn't this time around as I took all these at Longwood Gardens. Merkle's Orchids however has a great rundown on orchid flower morphology.

A hybrid containing Cattleya, another popular though more difficult orchid

I'm hoping to get a few more orchids for myself at some point. Planning on trying to grow a Paphiopedilum as well as a Bulbophyllum which I think I'll need to grow in a hanging basket. I was actually going to buy them last year but held off when I learned I'd be moving to Delaware, so I'll see if I can find the money this time around.

A little later this week we're going to revisit Tree ID, and learn how to identify a few Pines.

Magnolia biondii

So I'm taking a brief break from my planned adaptation/living planet themed entries to show off a few more photos... I did make it to Longwood's Orchid Show last week, and am hoping for another visit shortly so there's a post on orchids in the works, but in the meantime I have a few photos on Google+ available here if you can't wait...

Magnolia biondii

Anyway, If I haven't mentioned it earlier, Magnolias are probably my favorite genus of tree. In fact, I credit the Bigleaf Magnolia (Magnolia macrophylla) with being the plant that got me interested in horticulture, botany, and eventually Botanic Garden Curation. I'll focus on that one later this summer when it is in bloom, but suffice to say it truly challenged my perceptions of what a tree could be, and furthered my appreciation for botanical biodiversity to the extent where I became passionate about sharing these realizations with others.

Framed by a fruiting holly for reference

As far as I know, this is the first Magnolia to bloom, and with them being a tree already known for early spring flowering that should say something. Seeing Magnolia biondii begin to push out flowers in late February or early March is quite regular, though whether or not it ends up getting away with jumping the gun in this fashion varies from year to year. More often than not, winter is not quite ready to depart yet, and another cold snap causes the tree to abandon  the process.

I'd seen the tree begin to break bud here at UDBG after a string of fifty degree days (which coincided with my first ride down DE Route 9 for the season), but when I saw the temperature was going to hit 60 last week I really began to take note. I've never really seen the flower do much more than break bud during my time living in New England, but given my move a little further down south as well as an unconditionally warm winter, I was in a pretty good position to see this flower fully open.

About the best I could do for a closeup... Tree is about 25' tall so
I couldn't zoom in on anything too close... this is cropped

It's definitely a smaller flower than you'd see on later spring magnolias such as the Star or Saucer Magnolia, and the tree as a whole is certainly less prolific in terms of flowering, though it's hard to say for sure if this is characteristic of the species or if this specimen is just struggling. Regardless, I think the flower itself is still interesting. Though not as showy, it is easily recognizable as that of a magnolia, probably closer to Magnolia cylindrica than anything else I've seen. Most noticeably, the pink coloration towards the base is deep, distinct, and prominent.

Maybe it's just that I've been watching Living Planet and am thinking in terms of adaptations, but I'm now puzzled by the early flowering time of this species. Is there in fact a pollinator which operates at these lower temperatures? Or is this an example of Magnolia biondii behaving differently in terms in cultivation versus the way it does in the wild? Unfortunately I don't have a book to reference at the moment as I left my copy of The World of Magnolias at school for a side project I'm working on, but I'll look into it tomorrow and see if I can come up with a better guess.

I'm not sure how much more these flowers will open, but with the weather forecast claiming 60 again tomorrow, I plan on having my camera with me most of the week. I've even spotted a few buds closer to eye level so this might not be the last we see of this tree this year.

Hopefully within the week I'll have the Orchid entry planned out... it's probably going to be a long one but I'm real happy with the photos so far so I'm thinking it will be a good one.

Fresh Water

Cover art from Wikipedia

I've been rewatching The Living Planet as of late, a classic nature documentary series from David Attenborough (his second actually) which aired in the early to mid 1980s. Though visually it can't quite stack up to some of his more recent work such as Planet Earth, it is interesting to see him taking a more active on-screen role in this series including acts such as narrating the segment on the oceans while in a diving suit, experiencing zero-gravity in a plane during the segment on the skies, and climbing to the top of a canopy tree in the jungle (during which he allegedly left his microphone on, treating his crew to a mix of panic, prayer, and profanity the entire way up).

One thing that really made The Living Planet unique however was that it really focused on the adaptations that various creatures of the earth had developed in order to more successfully survive in their environment. I thought it might be interesting to pick a plant species which would grow in each of these habitats, and cover some of the adaptations or characteristics it displays which allow it to really thrive there.

The first topic covered in the series (at least on the DVD I have, a Christmas Present from my friend Dave a year or two back) is Fresh Water. I actually do have a few photos of freshwater plants which I took upon moving here when I was doing some volunteering at Longwood.

Nymphaea, the Water Lily

Obviously since this plant grows in water instead of upon land, there are a few additional challenges it faces. First off, light does not travel through water as well as air, so it would be difficult for a truly underwater leaf to photosynthesize very effectively. The way the water lily has circumvented this is to ensure that its leaves grow on the surface of the water, able to photosynthesize without losing any of the brightness of the leaf. In fact, in many aquatic plants, the chlorophyll in the leaf tends to be exclusively on the top side, though I'm not sure if this is the case in Nymphaea.

Leaves float (so long as they are alive anyway) due to air pockets within their leaves, which exist due to gas exchange taking place during photosynthesis. It is worth noting how thin and flat this leaf is however, ensuring that water is unlikely to pool up on top of the leaf and cause it to sink.

A Lotus (Nelumbo), at Blithewold

It's not merely the leaves which hold this plant up though. As you can see in the above photo, this plant does have stems connected to these leaves, which in turn connect to roots and anchor it to the bottom of the water body. The shoots tend to be hollow, decreasing their density and encouraging their floating as well.

However, this erroneously sort of portrays the plant as fearing the water. There are obviously a good deal of benefits for the plant resulting from being submerged in water. For one, water retention becomes a non-issue. Land plants have stomates (stomata) in their leaves, essentially pores for gas exchange. They try to keep these closed as much as possible to reduce transpiration. Since aquatic plants don't have to worry about drying out, their stomata tend to be open most of the time.

So, suffice to say, plants can grow just fine in the water, as long as they can keep their leaves out of it.

I actually forget what this is, but note that even though the margins of the leaves are raised, there are still "gabs" through which the water could run off were the leaf to become submerged. I think this plant may have actually had a few other tissues which aided in its floating but can't quite remember... I'll have to check back in the summer.

I'm not sure how regularly I'm going to do these (I'd like to do some more Tree ID over the next few weeks), but the next one will probably be on the Jungle, focusing on how epiphytic orchids use their roots (and probably a bit more on orchids as well as I want to get down to the Longwood Orchid show and take some pictures).

the birch

I was planning on writing a bit on Nandina domestica (Heavenly Bamboo), but the shots I took quickly on Sunday aren't quite up to the quality I'm holding myself to so I think I need to spend a little more time on that first.

However, did take some other photos over the weekend while preparing for a lab on native trees I'm teaching this semester. Though I took these more to emphasize easy identification characteristics instead of the ornamental appeal of the plant, I still think it's a good excuse to talk a little bit about one group of our native trees: the birches.

Paper Birch (Betula papyrifera)
Note the cluster of three male catkins on the end of the branch

The Paper Birch is probably the first one that comes to mind when I think of a birch tree. It's actually one of the first trees I remember being interested in as a kid. Growing up on the Vineyard I was used to seeing Black Oaks, White Oaks, Pitch Pine, Sassafras, the occasional Red Maple, and that was about it. I saw one while up in Maine one summer, and remembered being confused over how different it was than any tree I'd seen before, with the thin, papery white bark smooth and cool to the touch. Maybe still as a result of this, like many birches, I'd probably claim the bark is the most significant feature of this tree.

So if that's the case then why did I relegate it to the background in the above photo? I didn't even widen the depth of field enough to bring it remotely into focus. Well, I was trying to highlight a group of catkins (essentially clusters of petal-less flowers), as they serve as a good characteristic to distinguish it from a similar species, the Gray Birch.

Grey Birch (Betula populifolia)
With a solitary male catkin

The name Grey Birch typically refers to the bark of this species, which is evident in the photo above mostly because of the lighting. If you see these plants out in the woods together though, sometimes both the Paper Birch and Grey Birch will have sort of an off-white color to the bark making them hard to tell apart. However, on this tree the male catkins tend to be solitary, instead of clustered as in the Paper Birch.

Yellow Birch (Betula alleghaniensis)

You might also see female catkins on birches, which are a bit stouter, and generally not on the tips of the branches. If you're in doubt over whether you have a male or female catkin, try rubbing it back and forth with your fingers. The female catkins will break apart rather easily while the males won't. And of course, there are male and female catkins on this tree as there are independent male and female flowers.

Now for the next three I actually do have the bark in full focus. First up is the Yellow Birch, or Betula alleghaniensis. The botanical name of this changed at some point, so you may see Betula lutea in reference to this species. The name lutea refers to the yellow, or golden lustre to the bark of this species. Now "yellow" probably isn't the first thing that comes to mind when looking at this tree, but once you think to look for it, there is a bit of a dark golden tinge to the bark, interrupted by the pattern of thick, obvious lenticels - pores of the tree used for gas exchange.

Were you to actually scratch the thin layer of bark open, you'd pick up on a familiar somewhat sweet odor: Oil of Wintergreen. The odor will not be quite so strong however as it would be for the Sweet Birch (Betula lenta)

Sweet Birch (Betula lenta)

The Sweet Birch is a similar looking tree to that of the Yellow Birch, but lacks that golden coloration. The Oil of Wintergreen it produces serves as a flavoring agent in Birch Beer. I've never been a huge soda aficionado, so I had actually never tried this (well, or at least don't remember it) until a few years ago. It was OK. I had the Polar brand (Worcester's finest), so I'm not sure if that was the best direction to go. I'd say this tree is a little less ornamental than the other one's I've listed here, but has actually become rather important in New England ecologically speaking as it's starting to take over the forests traditionally inhabited by Eastern Hemlock, which are dying off due to the threat of Hemlock Wooly Adelgid.

River Birch (Betula nigra)

Finally, we have the River Birch, which can be readily identified by the reddish-tan colored bark, peeling off the plant with enough of a fervor to leave bare spots on the trunk. I'd say this is one of the more common birches cultivated in the landscape. For my friends in Boston, there's an aspiring grove of these about halfway down the Greenway (Somewhere between the Aquarium and the Intercontinental). They do put on a nice show in the fall when the leaves turn a brilliant yellow. I did find those trees a bit difficult to work with as I seemed to be constantly having to prune the lower branches, as well as water the trees heavily in the dead of summer, also proving difficult as the trees were planted on raised grass mounds which the water tended to roll off of. As the common name suggests, River Birches do like their water, and seeing the fall color show in mid-July can be a bit disconcerting.

Though I didn't explicit mention it throughout the article, I hope you're gaining a bit of an appreciation for some of the sight recognition tricks someone like me would use to quickly identify a birch tree while in the field. If I see a tree that I can identify as probably being a birch, to figure out which birch is a matter of asking myself a few questions: Is the bark peeling heavily? Do the twigs have a sweet soda-like smell when scratched? If so does the bark look golden? And if the bark is white, thin, and papery, how many male catkins does it display?

Next time you think you see a birch out in the woods try asking yourself the above and see what you come up with. Especially since you can't use the LeafSnap app since it's winter (though at 50 degrees again today I'm still not convinced).

and finally, the indehiscent fruits

Line drawing of Common Buckwheat from
wikipedia. Note the fruit in the lower right.