Pine Cone Botany For Beginners

The start of December means the start of “pre-Christmas”: the time of year when gifting stress sets in and your friends keep posting pinterest-worthy photos of their DIY holiday decorations. Who has time to hot-glue homemade ornaments and make garlands out of twine? It can induce a crippling case of craft-envy for people who have full time jobs and/or lack artistic prowess of their own.

For weeks I have been collecting pine cones from the Arboretum grounds, wishfully thinking I will find time to incorporate them into a hip holiday craft. The crafting is still on hold, but in the meantime I have become inspired by the cone itself! As the symbol of winter and the star of holiday decorating, we owe it to the humble pine cone to learn a bit about its fascinating botany before we dry it, paint it, wrap it in ribbon and hang it from the door knocker.

Pine Cones 101

Pine cones (and all true cones) are produced by a group of plants called gymnosperms. Pronounced just as it is spelled (gym-no-sperm) and originating from the Greek language, it translates to mean “naked seed”. The seed doesn’t get this label because of exhibitionist behavior, but because, unlike seeds of flowering plants, it develops outside of an ovary.

Public domain image from wikimedia commons - https://commons.wikimedia.org/wiki/File:Ovule-Gymno-Angio-en.svg

Don’t be intimidated by botany lingo, it’s actually pretty simple: embryo sac (nucellus) and dividing cell (megasporocyte or “mama cell”) make up the seed, which in non-flowering plants (gymnosperms) is unprotected by fleshy layers. Image from wikimedia commons

 

Since gymnosperms do not flower, they do not form a fruit as an ovary for their seed. Their cone is a rigid vessel for the developing seed which rests on the top of a scale. When the cone is mature and dries out the scales will open, dropping seeds.

pine cone edit

 

Male pollen cones do not make great holiday decorations

Male pollen cones, bad for decorating.

 

Seed bearing cones are female, while pollen filled cones are male. Both sexes of cones grow on the same tree,  but male cones grow on lower branches so that the wind can blow pollen up to the female cones. Likely all the cones you will collect for decorating are lady cones, since male cones are significantly smaller, softer and less conspicuous.

 

 

 

Pine Cone Diversity

Pines, cedars, and spruce trees are examples of common gymnosperms, but baldcypress, ginkgos and cycads are all unexpected members of this group as well. Cones from pine and spruce trees are my favorite to decorate with because of their classic Christmas charm and uniform scales, but you may want to hunt down some more exotic cones for yourself! The Arboretum grounds are home to many mature evergreens currently bearing cones, each with their own charisma.

Cones of the Arb

From left to right: Norway Spruce, Pinion Pine, Austrian Pine, Austrian Pine (Opened), Ponderosa Pine, White Pine, Black Hills Spruce.

Lesser-known Cones

Alder flowers look like tiny cones!

Alder flowers look like tiny cones.

I must note that some of my favorite cones are not true cones at all!  The alder tree on the east border of the Arboretum makes adorable little cones as big as your thumb tip, yet this species is not a gymnosperm.

These cones are actually flowers that resemble their cone-bearing ancestors; flowering plants evolved from gymnosperms, yet alder trees have retained some characteristic reproductive structures.

If you can’t impress your friends with precision gluing and glitter technique this holiday season, impress them with your botanical knowledge! They may wish they had spent less time slathering peanut butter on pine cones  and more time learning about them.

 

 

Not-So-Sweet Smells of Fall

Fall is a wonderful time to be the Arboretum grounds keeper – watering duties slow down, weeds are relenting, and I can wear my favorite sweaters to work. Brisk mornings and the coppery hue of the landscape make for a pleasant work week.

But wait … what’s that smell?

Working in many different areas of the Arboretum has led me to discover some autumnal aromas that are downright unpleasant. It isn’t the cinnamony smell of pumpkin spice latte on the wind, but a stench of skunk and old cheese! Early fall moisture and warm days bring out the worst of smells in some of our flowers and shrubs, causing me to cringe when working near the fetid few.

If you have visited us recently, perhaps you too are wondering about the foul air. Wonder no more! I introduce to you the top three smelly plants at the Arboretum:

1. Cypress (Cupressus arizonica)

While cypress trees traditionally have a pleasing aroma, this variety emits an odor redolent of skunk. The icy blue foliage may be off putting at first sniff, but if you rub the needles between your fingers the scent becomes influenced by citrus and spice, making it somewhat less offensive and almost forgivable. Almost.

(Left) Arizona Cypress tree in the Northwest corner of the Arboretum. (Right) Cypress foliage

(Left) Arizona Cypress tree in the Northwest corner of the Arboretum. (Right) Cypress foliage

Many evergreens have strong scents, and they get their classic “Christmas” smell from gummy resins, which contain high concentrations of terpene alcohols and acids. Unfortunately, this tree smells less like Christmas and more like roadkill.

 

Penstemon digitalis seed pods near Dyck Arboretum Visitor's Center

Penstemon digitalis seed pods

2. Penstemon (Penstemon digitalis)

Penstemon is a showy spring bloomer that produces reddish, tear-drop shaped seed heads. But when you decide to cut those seed heads down for clean up or collection, I suggest pinching your nose! The bloom doesn’t have a strong scent, but the smell of the seeds and pods has been likened to animal vomit, or very acidic urine. The seeds themselves, though tiny, seem to make the biggest stink – after handling seed, it takes many rounds of hand washing to remove the tangy, kitty-litter smell from your fingers.

 

3. Rough-leaved dogwood (Cornus drummondii)

Dogwoods grow in dense thickets and are a popular choice for creating natural borders. Because of their thick cover, they are attractive to wildlife and nesting birds. But they are not attractive to the human nose. Dogwood leaves smell ever so slightly of curdled milk. In calm, humid weather, walking near our dogwood plantings can feel as if you have a dirty gym bag on your face. Luckily, as cooler weather sets in, the foul air around these plants seems to dissipate.

So, why the big stink? For flowering species, exuding sweet smells is a signal to bees and butterflies that nectar is ready. No two floral scents are alike in molecular makeup, allowing for specific pollinator attraction. Most plants that give off an unpleasant balm are attracting a less charismatic type of pollinator – flies and beetles. If not for pollination purposes, a malodorous plant may be using its sour perfume as protection from herbivores such as rabbits and deer.

Whatever the reason, I won’t hold the smell against them…but I may choose to avoid pruning them for as long as I can get away with it!