Between Leaves and Shapes: A Journey to the Universe of Araceae

Generally, aroids are recognized by their arrow-shaped leaves of green color, lustrous and resistant. However, many of them have leaves in other shapes, sizes, and color variations. There are species whose leaves can surpass two meters of length. As for their format, there is a wide variety within this group. Leaves can be arrow-shaped (sagittate), heart-shaped (cordiform), spear-shaped (lanceolate), with flat, cut, undulated, or sinuous leaves, in addition to many other interesting details that make the difference for people curious about or already initiated in the art of gardening. Such impressive diversity and adaptability to indoor environments explain the increasing amount of people interested in cultivating this family at home, becoming true arum collectors!

From bright green to vinaceous-purple, the colors of the aroids bring life to external gardens, apartments, and floral arrangements. More than that, the colors and textures often indicate the appropriate place to grow them. In the vegetal world, shades of red and purple might be related to the production of anthocyanin, a pigment that protects the plant from sun rays. Red and purple leaves often have a more intense coloration when exposed to the sun, since these pigments act as some sort of sunscreen. On their turn, variegated leaves, those with spots of colors other than green, manifest due to the absence of chlorophyll or by the predominance of other pigments, such as the previously mentioned anthocyanin. The variegation can appear naturally as a mutation of the plants, a feature frequently preserved by ornamental growers in search of unique aesthetic effects. However, unpigmented plants do not tolerate low brightness and are sensitive to sunlight exposure.

The aroids are usually known for their ornamental foliage, but many of these species have striking flowerings! As in the picture, the inflorescence (set of flowers) typical to an aroid has a thick, fleshy axis sustaining minuscule flowers, protected by a modified leaf, the spathe, that can also attract pollinators. When there is pollination, these flowers go through an extraordinary transformation and turn into succulent fruits. When the seeds are fully formed, steeped in mucilaginous pulp, the plant announces a new need: it is the time of dispersal agents. Most animals are attracted by bright colors, and many Araceae respond to this fact by changing the color of their unripe fruits to red, orange, yellow, or purple. The succulence and the sweet flavor of fruits are also a strategy to increase the chances of consumption by the fauna.

Despite the fact of being predominantly climbers, the Araceae can also take the form of herbs and bushes. In this group, there are examples of geophyte (tuberous and subterranean stem), epiphyte (on other plants), rupicolous (on rocks), and helophyte (plants growing in soaking or flooded grounds). This way, the aroids occupy a variety of environments and develop appropriate structures in each of them to allow for their survival. The roots, for instance, can be subterranean, aerial, or aquatic, and each of them has different features and functions, such as fixing in soil, keeping in support, or absorbing nutrients. The main threat to the Araceae is the loss and reduction of quality in their natural habitats. Some species are highly adapted to specific environments and cannot survive under altered conditions. The removal of tropical forests eliminated most of terrestrial, climber, and epiphyte species, since many of them require a shaded environment.