An online resource based on the award-winning nature guide


Abscission Layers Forming


As the days grow shorter and the nights longer, cells near where a leaf’s stem joins a tree’s branch start to divide rapidly. This is the start of the creation of the corky layer of cells known as the abcission layer.

The annual growth of a tree ends with the formation of the abcission layer. This layer prevents the transport of materials such as carbohydrates from the leaf to the branch and it blocks the flow of minerals from the roots into the leaves. Chlorophyll, critical to the process of photosynthesis, breaks down with exposure to light and is replaced continually by the leaves during the summer. When the abcission layer forms, this is no longer possible.  The chlorophyll slowly breaks down and disappears, revealing the underlying xanthophylls (yellow pigments) and carotenoids (orange pigments) that the chlorophyll was masking. These pigments, in addition to the red pigments (anthocyanins) that are manufactured from sugars trapped in the leaf, provide us with our brilliant foliage.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.

Early Splashes of Maroon

10-6-16-white-ash-leaves-20161005_4124At this time of year, our eyes are immediately drawn to the brilliant orange, red and yellow pigments of Sugar Maple (Acer saccharum) leaves. However, there’s much to be said about the less flamboyant splashes of color adorning some of the species of trees that provide New England’s spectacular fall foliage. One such subtley-colored fall tree that often grows in upland forests along with Sugar Maples is White Ash (Fraxinus americana). One of the first trees to change color in autumn, White Ash can turn shades of yellow, orange and red, but deep red, maroon and purple are typically the grand finale of this species. Often its leaves progress from green to yellow and eventually maroon.  While it might not be the first tree that catches your eye, make a point of looking for its colorful, compound leaves – you won’t be disappointed.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.

Woolly Oak Leaf Gall

11-28-14  woolly oak leaf gall IMG_3574Of the 2,000 kinds of galls found on North American plants, 800 different kinds form on oaks. One of these is the woolly oak leaf gall, produced by a tiny Cynipid wasp, Callirhytis lanata. This gall is usually attached to the mid-vein on the underside of an oak leaf, and looks like a ball of wool. It may be as large as three-fourths of an inch and is often bright pink or yellow in color, fading to light brown in the fall. Oak trees have lots of tannic acid in them (a defense which makes the tree unpalatable to herbivores), with the highest concentration found in oak galls. (The bitter taste is where the name “gall” originated.) It’s possible, since tannins are somewhat anti-microbial, high-tannin galls such as the woolly oak leaf gall may protect the larva against fungi and bacteria.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.

Goldenrod Bunch Gall

goldenrod bunch gall 144Galls are abnormal plant growths that are caused by a number of agents, including insects. Each gall-making insect has a specific host plant and location (leaf, stem, bud) on which it lays its eggs in the spring, during the growing season. The egg-laying and/or hatching and chewing of the larva causes the plant to react by forming a growth around the insect. Galls of different species of insects vary in their shape and the gall maker can often be identified as a result of this.

Goldenrods are host to about 50 species of gall-making insects, two-thirds of which are midges, or tiny flies. Goldenrod Bunch Galls, also called Rosette Galls, are the result of an egg being laid in the topmost leaf bud of Canada Goldenrod, Solidago canadensis by a midge in the genus Rhopalomyia, often Rhopalomyia solidaginis. The stem of the goldenrod stops growing, but the leaves don’t. The resulting rosette of leaves provides shelter and food for the midge larva, as well as a host of other insects, including other midges. Adult Goldenrod Bunch Gall midges emerge from the galls in the fall, and females lay eggs in the soil. The larvae hatch within one to two weeks and spend the winter underground, emerging in the spring to start the cycle all over again. Interestingly, Rhopalomyia solidaginis lays all male or all female eggs, one or the other.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.


February 14th

2-14-14 leaf heart  038

Red-eyed Vireo Nest

10-31-13 red-eyed vireo nest  033 Abandoned bird nests are evident now that leaves have fallen off the trees. Consider the time and effort that goes into the construction of one of these single-use nurseries. Take the Red-eyed Vireo’s nest you see here lying on the forest floor. The female selects a nesting site — a time-consuming task, as the requirements are that it conceal the nest and provide shade for her young. (Too much sun will cause her to abandon the nest. One female who had selected a sunny spot was observed pulling nearby green foliage over her nest and fastening it in place with spider webs.) The female vireo then collects nesting material for the three layers of her nest: Exterior – tree bark, spider-egg cases, wasp-nest paper, lichen, green leaves and pine needles. (Nests exposed to sunlight may be decorated with light-colored tree bark such as birch bark.) Interior – bark strips and plant fibers. Inner lining – grasses, pine needles, plant fibers and animal hair. She then weaves these materials into a cup-shaped nest that is suspended from a forked branch by its rim. A trip for materials is made every 3 – 11 minutes and roughly twenty seconds is spent working each load into the nest structure. This intensive work takes the female vireo approximately five days – all accomplished without the aid of any hands or tools, and she only uses the result of all this work once. Fortunately, recyclers make good use of her efforts.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.

Pitcher Plants Turning Red

10-29-13 pitcher plant2 158 Pitcher plant leaves are primarily green in the summer, tinged with red, but as summer turns into fall, many become deep red. Although this red color was thought to attract insects, it appears that this is not the case. The color change, according to research cited in the Journal of Ecology, is due to the level of phosphorus this carnivorous plant has received from its insect meals. There is a limited amount of phosphorus in a bog and plants living there acquire it in different ways. The pitcher plant acquires phosphorus from insects that it traps. It then utilizes the phosphorus to revitalize the (green) chlorophyll in its leaves for photosynthesis. The deep red color that the leaves turn in the fall indicates that the plant has not had a good meal in quite some time.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.