Cryptic cladophylls – stems hiding in plain sight

One of my favorite topics back when I taught Botany 101 was plant oddities. A recent question on our Garden Professors’ discussion group on Facebook reminded me about cladophylls, like the one pictured below.

Terminal stem of Schlumbergera

Cladophyll literally means “branch leaf.” Anatomically it’s a branch (it has nodes from which new stems, leaves, flowers, and even roots can arise), but it functions as a leaf. It’s the main site of photosynthesis in plants such as holiday cacti (Schlumbergera species). Like other cacti, they have reduced leaves and if you look closely at the photo, you can see the leaves as tiny hairs arising from the nodes at the end of the stem and along the sides.

But unlike cacti, these plants aren’t found in deserts, and their leaves are soft threads rather than the vicious sharp spines you’ll find in typical cacti. Instead, these are generally epiphytes in coastal mountains where humidity is relatively high. But root water is limited for epiphytes and these waxy cladophylls probably are adaptations against water loss. Their reduced leaves are immune to drought stress, unlike those of other succulents which appear only when water is plentiful.

Euphorb leaves will drop when water is unavailable

As you might expect from their red, tubular flowers, holiday cacti are pollinated by hummingbirds in their native environment. Gardeners who have a sufficiently mild climate to grow these outdoors might be lucky enough to see them visited.

Schlumbergera flower

Published by

Linda Chalker-Scott

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU’s Extension Urban Horticulturist and an Associate Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors "The Garden Professors" Facebook group - www.facebook.com/groups/GardenProfessors Books: http://www.sustainablelandscapesandgardens.com

2 thoughts on “Cryptic cladophylls – stems hiding in plain sight”

  1. Fascinating. New term for me.

    I noticed at the Facebook group, the thought for the blog post was prompted by someone asking about the potential for green stems to photosynthesize … and when I shared this post to the GP FB Page, asparagus was mentioned as falling into the cladophyll category.

    And, I did some googling, and came to the conclusion that any plant tissue (leaf, stem, even fruit) that has chloroplasts has the potential to photosynthesize, although how much it adds to the plant’s overall food-making seems to depend completely on which plant.

    Please clarify, or add anything to help me (and hopefully others) to better understand.

    1. You’re right, Ray. Anything that’s green (other than potatoes) contains chloroplasts and is photosynthetic. How much any particular tissue contributes to overall sugar production depends on how much those tissues dominate the overall plant.

      Cladophylls, as I should have mentioned, are photosynthetic stems that are flattened – thus, they not only function as leaves but kind of look leaflike. So asparagus and cacti (the regular type) have dominant, photosynthetic stems and reduced leaves, but their stems are not cladophylls.

      Hope that helps!

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