Archive for category: Plant knowledge

A glance into nature reveals ripe dogwood cherries lying on the ground, and autumn crocuses have faded away. A new phenological season begins: Full Autumn. Perhaps it will bring us a “Golden October” with many warm days, but weather is not an indicator of phenology. Phenology observes the annual developmental cycle of plants, and thus, Full Autumn is defined by the fruit ripening of the pedunculate oak, followed by late pear varieties and grapevines. The highlight is the foliage coloration of the horse chestnut. Full Autumn comes to an end when the leaves of the European beech and pedunculate oak change color and begin to fall. On average, Full Autumn lasts from September 17th to October 19th.

Acorns

The pedunculate oak (Quercus robur) belongs to the beech family. It is widespread in Europe and tolerates both (short) waterlogging and dry periods. Consequently, it is found both in lowlands and at elevations of up to 100 meters above sea level. In April-May, the pedunculate oak blooms, and by then, its namesake feature becomes apparent: the flowers (and later the acorns) are borne on 4-6 cm long stalks. Acorns are an important food source for many bird and mammal species (jaybirds, squirrels).

Late Pear Varieties

Comparing apples and pears is rarely a good idea, but one thing can be said: pears (Pyrus communis) need more warmth than apples to unleash their full flavor. Early pear varieties must be consumed quickly and are not suitable for storage. The fruits ripening in autumn can be stored – depending on the variety – well into winter. Classic aromatic pear varieties include Conférence and Gellerts Butterbirne. Among the novelties, the productive variety “David” stands out with firm, sweet, juicy fruits, ripening from early to mid-October.

Grapes

The grapevine (Vitis vinifera) is the Medicinal Plant of the Year 2023 because its fruits (grapes) are rich in secondary plant compounds. These are mainly concentrated in the seeds of the berries. However, they can also be found in the skin and leaves of red grapes. To determine if a grape is ready for harvest, check if all its berries are colored, the fruit stalks are woody, and the seeds inside the berries are brown, not cream-colored, and easily separate from the surrounding pulp. Grapes are best cut off completely from the vine with scissors and can be stored in the refrigerator for up to 14 days – provided spoiled berries are removed beforehand.

Horse Chestnut

There are several species within the horse chestnut genus, but phenologically interesting is the common horse chestnut (Aesculus hippocastanum). By the way, the sweet chestnut, Castanea sativa, from which delicious chestnuts come, is not related to horse chestnuts! The horse chestnut originates from the mountainous regions of the Balkans and has been widely planted as a street tree in Central Europe since the 16th century. White-flowering horse chestnuts often suffer from infestation by the horse chestnut leaf miner. This leads to premature wilting and dropping of leaves in August to early September. If you want to document the foliage coloration of the horse chestnut as an indicator for phenology, please use healthy trees.

This article was displayed in the Flora-Incognita app as a story in autumn 2023. In the app, you can find exciting information about plants, ecology, species knowledge, as well as tips and tricks for plant identification. Why not take a look!

The dog days are over, marking the end of the warmest time of the year. Now, we find ourselves at the beginning of a new phenological season: early autumn. Phenological seasons are characterized by specific developmental stages of certain indicator plants, including flowering, leaf unfolding, fruit ripening, autumn leaf coloration, and leaf fall. The early autumn, which is beginning now, is characterized by the fruit ripening of elderberries and cornelian cherries. Let’s take a closer look and explore the other events that await us in the next (approximately) four weeks.

Ripening Elderberries

The elderberry (Sambucus nigra) is one of the most common shrubs in Central Europe. Botanically, the “berries” are classified as drupes. They are rich in vitamin C and potassium, and are edible after cooking. However, when consumed raw, some people may experience nausea or vomiting due to the presence of plant toxins. In herbal medicine, their juice is considered a remedy for colds, kidney and bladder problems, and for strengthening the heart and circulation. They are also used in cooking: in elderberry soup with semolina dumplings or rusks, as jelly, juice, or fruit wine – the possibilities are numerous.

Vibrant Red Cornelian Cherries

Is it a large shrub or a small tree? Both forms can be found in cornelian cherry (Cornus mas) specimens. Mature specimens can grow up to 8 meters tall with a trunk diameter of 45 cm. Its glossy red fruits, about 2 cm long, are classified as drupes and have a similarly red, sour flesh. This flesh contains 70–125 mg of vitamin C per 100 g. The fruits can be eaten raw, dried, frozen, or processed into liqueur, wine, juice, jelly, and jam.

Autumn Crocus Blooms

Autumn crocus (Colchicum autumnale) is a herbaceous, highly poisonous plant. One to five flowers sprout from its bulb. It can be found in moist meadows or open floodplain forests. The crocus-like flowers emerge without leaves – the leaves grow in spring and are quite similar to wild garlic. The pale pink to violet flowers, about 20 cm long, are significantly larger than regular crocuses (some of which also bloom in autumn). To distinguish them, count the stamens. Autumn crocus has six, while regular crocuses have three.

Sunflowers ready for harvest

By the end of August, sunflowers (Helianthus annuus) are ripe – provided they receive enough sun and water during their 150-day growth period. You can tell they are ready for harvest by the browning of the seeds in the center of the flower head and the ease with which they detach. The back of the flower head also turns brownish-black. It’s best to cut the entire flower head and then shake out the seeds – in stubborn cases, a small brush can help access the seeds. Stored washed and dry, you can peel and roast them for snacking, or leave them raw to provide wild animals with food during the cold season.

This article was featured as a story in the Flora-Incognita app in the summer of 2023. In the app, you can find exciting information about plants, ecology, species identification, as well as tips and tricks for plant identification. Why not take a look?

Every year, a clear chronological sequence of events such as the beginning of flowering, fruit ripening, or leaf coloring of specific plant species repeats itself. Thoroughly documented, phenology provides important data on the changes in regional climate – benefiting, for example, farmers who can adjust their tasks like sowing and harvesting according to the corresponding developments in plant life. Moreover, large-scale climatic changes can also be mapped using phenological data. Plant identifications with Flora Incognita assist in documenting phenology worldwide. Thank you for your contribution! The phenological late summer in Germany typically lasts only about 18 days. The official indicator of this season is the picking ripeness of early apple varieties, but there is much more to discover!

Early Apples are Ready to Pick

The White Transparent apple (Malus domestica), originating from Latvia, has been widespread in Europe since the end of the 19th century. This old variety is known for its early ripening from late July and its short shelf life: the fruits become mealy and spoil after about 2 weeks. For professional cultivation, the variety is no longer relevant, but it can still be found in many gardens. We are sure: many apple pies will be baked this year from the first White Transparent apples of the season. Other early apple varieties include James Grieve, Julka, Paradis Katka, Piros, and Retina.

Ripening of Serviceberries

The Serviceberry or Juneberry (Amelanchier lamarckii), native to the USA, is popular in Europe as an ornamental shrub due to its spring blossoms and magnificent autumn colors. Its almost black and sweet fruits ripen in late July and can be dried and used like currants. Unlike true currants, which are dried berries of the Corinth grape variety (Black Corinth), Juneberries belong botanically to the rose family. The Common Juneberry (Amelanchier ovalis), which is native to Germany, also ripens in July. Many birds love the small, dark fruits, but they are also a great choice for making jam or liqueur.

Rowanberries are Ripe

Rowanberries are the fruits of the mountain ash tree (Sorbus aucuparia). They ripen from August into early autumn. Botanically, they belong to the pome fruit family – if you examine a fruit closely, you will see that it looks like a tiny apple! Rowanberries often hang in clusters on the tree throughout winter and are an important food source for songbirds during this time. Did you know? Overripe fruits can develop significant alcohol content through the anaerobic fermentation of sugar components! For example, starlings or waxwings can easily tolerate a blood alcohol level equivalent to 0.3‰. Both their digestive tract and metabolism are adapted to this effect.

Heather is in Bloom

Late summer is also the time when heather (Calluna vulgaris) begins to bloom. This evergreen dwarf shrub can live up to 40 years and grow up to one meter tall – provided its growth is undisturbed. The white to purple, 1-4 mm long flowers form in clustered inflorescences and provide ample nectar for many wild bees, butterflies, and honeybees. Fans of heather honey appreciate its bitter aroma and jelly-like consistency. In many flower boxes, cultivated varieties of heather can be found in a variety of colors, including variants that maintain these colors for weeks. Please note, these are so-called bud bloomers, whose flowers never open – they are inaccessible to bees and other insects!

This article was featured as a story in the Flora-Incognita app in autumn 2023. The app provides fascinating information about plants, ecology, species identification, as well as tips and tricks for plant identification. Feel free to explore!

The leaves of a plant are often a crucial feature for species identification: the leaf of the Wych Elm (Ulmus glabra) has a serrated edge, the leaves of the Wild Tulip (Tulipa sylvestris) are soft and hairless, and the leaves of the Guelder Rose (Viburnum opulus) are always arranged oppositely. There are many examples of plants whose leaves look so unmistakably that the corresponding species can be confidently identified. However, this does not apply to all plants! Some species respond to environmental influences by changing certain characteristics of their leaf shape, such as the size of the leaf surface or the density of leaf venation.

“Leaf polymorphism” (heterophylly) means that a single plant can have very differently shaped leaves. Some herbs can produce several very different leaf forms, so distinct that they might not be attributed to the same species. A notable example of this is found in some species of the genus Ranunculus, commonly known as buttercups. For instance, the Water Buttercup (genus Ranunculus, section Batrachium) has two completely different leaf forms: the finely divided leaves underwater (submerged leaves) and the roughly three-parted dissected leaves that float (floating leaves).

To understand the phenomenon of heterophylly, one must consider the genetics of the plant. The Water Buttercup has a genotype, a genetic basis for its plant traits, but two different leaf phenotypes (physical appearances). Through years of research, even at the molecular genetic level, scientists have determined which genes need to be activated to initiate the formation of a specific leaf shape. The role of plant growth hormones, their concentrations, and flows that determine the final leaf shape has also been investigated. In the case of the Water Buttercup, the pronounced leaf polymorphism is an adaptation to the environment.

However, there are also examples of leaf polymorphism that remain mysterious to this day, as they cannot be explained by environmental adaptations. Among the early spring plants that push their leaves out of the ground, there is the Goldilocks Buttercup (Ranunculus auricomus agg.). What sets this group of species apart is that the same plant can produce completely different leaf forms, depending on whether it has just emerged from winter dormancy, whether it is flowering, or fruiting.

Within a plant individual, an entire leaf cycle occurs, starting with relatively small and simply three-parted leaves (initial leaves) that emerge immediately after winter. Around April, when the plant starts to bloom, more or less deeply divided leaf forms appear, typically used for species identification. Later in the year, when the plant is fruiting, less dissected leaf forms reappear (summer leaves, final leaves). These resemble the initial leaves but are larger. Why the Goldilocks Buttercup exhibits such leaf diversity within a year remains unclear. An adaptation to the environment, as in the case of the Water Buttercup, could not be demonstrated here.

What remains a puzzle for plant development poses a real challenge for botanical systematists. How can one reasonably morphologically define a plant species like the Goldilocks Buttercup when it constantly changes throughout the year? A tough nut to crack (and a subject of ongoing refinement) even for Flora Incognita!

This article was featured in the Flora-Incognita app as a story in the summer of 2023. The app provides intriguing information about plants, ecology, species identification, as well as tips and tricks for plant identification. Why not take a look?