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Araceae


Araceae

Background:Part of a poster that sold with the 1991 Missouri Botanical Garden calender.


Monstera deliciosa2
Philodendron bipinnatifolia3
Dracunculus vulgaris tuber picture from Wikimedia Commons
Amorphophallus koratensis tuber

Abbreviated aerial stems, seen in epiphytic species like Philodendron, and larger arborescent forms in Alocasia, Xanthosoma, and Philodendron showcase the family’s varied growth habits. Specialized shoot types, such as flagelliform shoots for vegetative reproduction, exist in several genera.

Shoot organization varies widely, with a sympodial structure in most genera. Continued growth involves the development of a “continuation shoot.” Floral sympodia, producing multiple inflorescences, exhibit structural complexity, notably in Homalomena. Unique shoot arrangements are observed in Gymnostachys, while some tribes like Potheae and Heteropsis display lateral short shoots on monopodial axes.

This intricate diversity in shoot structures provides valuable insights for the taxonomy of the Araceae family.

Leaf:The leaves in most Araceae genera are distinctly structured with an expanded blade, petiole, and petiole sheath, although exceptions like Gymnostachys and some Biarum species exist. Sympodial leaves, often with reduced sheaths, are observed in Philodendron, especially when the apex without developing an inflorescence.

Araceae exhibits remarkable diversity in leaf size and shape, ranging from diminutive to gigantic. Shapes include linear, elliptic, ovate, cordate, sagittate, hastate, trifid, pedatifid.

Heteroblasty, observed in climbing genera, is a taxonomically useful characteristic. Certain genera, like Monstera and Pothos, exhibit “shingle plants,” with juvenile leaves having short petioles and blades lying flat against the host tree.

Inflorescence: The Araceae inflorescence consists of an unbranched spike (spadix) with numerous small, usually spirally arranged flowers, subtended by a specialized bract called the spathe. Notably, spathe and spadix modifications vary, showing an evolutionary trend towards synflorescence. Major modifications include loss of perigone, specialization of flower zones, and spathe differentiation. Specializations also involve diverse odors, color patterns, and persistence variations. Terminal appendices on the spadix, found in various tribes, function in pollinator attraction. Flowers may be 2- or 3-merous, exhibiting unique structures. Gynoecium variations include locule numbers and diverse placentation types. Stigmas are wet, with variations in lobing and size, particularly in Monsteroideae.

Alocasia odora flower
Amorphophallus titanum flower
Dracunculus canariensis fruits4

Distribution

Etymology5

Genera6

First Description7

  1. Boyce and Croat, 2023 ↩︎
  2. Wikimedia Commons ↩︎
  3. Wikimedia Commons ↩︎
  4. Wikimedia Commons ↩︎
  5. Wikitionary ↩︎
  6. Boyce and Croat, 2023 ↩︎
  7. BHL ↩︎