The long-and-short of lycophytes

I don’t do plant-free holidays, and one of the species I wanted to photograph during my recent Northland holiday was the tiny and rare Phylloglossum drummondii.

Phylloglossum drummondii, less than 2 cm tall, in a Northland swamp.  For scale, there is a manuka fruit in the background.  Photo © Leon Perrie.

Phylloglossum drummondii, less than 2 cm tall, in a Northland swamp. For scale, there is a manuka fruit in the background. Photo © Leon Perrie.

This diminutive plant has a Nationally Critical conservation ranking, because of its low numbers and the destruction of its swamp habitat. Finding it necessitates a winter (or early spring) field trip, as it survives the summer heat (and fires?) as an underground tuber. It is the world’s only species in the genus Phylloglossum, and it is only found in Northland (having become extinct further south) and Australia.

Phylloglossum drummondii reproduces by spores produced from capsules on the modified leaves making the ‘cone’ at the top of the central stem. It is a lycophyte. Lycophytes are the oldest but now least-diverse of the three surviving groups of land plants with specialised vascular tissues for the internal transport of fluids. The others are ferns and seed plants. Ferns are like lycophytes in that they disperse by spores and do not produce seeds, but ferns are actually more closely related to seed plants. Lycophytes and ferns differ in that the leaves of the former are small (‘microphylls’) whereas the leaves of ferns are generally big (‘megaphylls’, or reduced versions thereof).

Modern lycophytes are only small plants. But before seed plants evolved, they included tall trees that dominated the landscape. Many of our fossil fuels are the remains of lycophytes.

Wikipedia’s page on lycophytes.

Phylloglossum drummondii looks very different from anything else alive. Its closest relative in New Zealand is probably Huperzia australiana. This has erect, leafy stems, and produces its spore capsules on unmodified leaves. However, take something like Huperzia australiana, shorten it, cluster the leaves with the spore capsules into a ‘cone’ at the stem’s apex, and, of the other leaves, keep only those in a basal whorl, and – hey-presto – you have Phylloglossum drummondii.

The (opened) spore capsules of the lycophyte Huperzia australiana, at the base of unmodified leaves. Photo © Leon Perrie.

The (opened) spore capsules of the lycophyte Huperzia australiana, at the base of unmodified leaves. Photo © Leon Perrie.

The erect, c. 15 cm, leafy stems of Huperzia australiana. Photo © Leon Perrie.

The erect, c. 15 cm, leafy stems of Huperzia australiana. Photo © Leon Perrie.

Perhaps the most common lycophytes to be seen in New Zealand are Huperzia varia and Lycopodium volubile, not to mention the exotic and terribly weedy Selaginella kraussiana.

Huperzia varia usually grows pendulously from trees or rocks. Photo © Leon Perrie.

Huperzia varia usually grows pendulously from trees or rocks. Photo © Leon Perrie.

Lycopodium volubile often scrambles up through other vegetation. Its leaves that produce spore capsules are modified and aggregated into ‘cones’. In this species, the cones are pendulous, but other lycophytes have erect cones. Photo © Leon Perrie.

Lycopodium volubile often scrambles up through other vegetation. Its leaves that produce spore capsules are modified and aggregated into ‘cones’. In this species, the brown cones are pendulous, but other lycophytes have erect cones. Photo © Leon Perrie.

Caption: Selaginella kraussiana is indigenous to Africa, but has become a widespread weed in New Zealand. It is problematic because it can carpet the ground, smothering small native plants and seedlings. Photo Leon Perrie. © Te Papa.

Selaginella kraussiana is indigenous to Africa, but has become a widespread weed in New Zealand. It is problematic because it can carpet the ground, smothering small native plants and seedlings. Photo Leon Perrie. © Te Papa.

If Phylloglossum drummondii was the short-of-it for my holiday, the long-of-it was finding record-breaking plants of two other lycophyte species.

According to the Book (New Zealand Ferns and Allied Plants), both Huperzia cernua and Lycopodium deuterodensum grow up to 100 cm high. I hope, then, that you can appreciate my surprise at finding the giants depicted in the botanical-selfies below. In both cases, they were semi-supported by other vegetation, but they are still rooted in the ground and I’m standing upright at a tick under 1.8 m (no tricks involved).

Me and the giant, 1. Huperzia cernua, near Pukenui, Northland. Photo © Leon Perrie.

Me and the giant, 1. Huperzia cernua, near Pukenui, Northland. Photo © Leon Perrie.

Caption: Me and the giant, 2. Lycopodium deuterodensum, Karikari Peninsula, Northland. Photo © Leon Perrie.

Me and the giant, 2. Lycopodium deuterodensum, Karikari Peninsula, Northland. Photo © Leon Perrie.

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