I am very pleased to welcome Andre Jagger - who specialises in Botany, Mycology and Biochemistry - and who lives in Hong Kong for a couple of days of guest blog posting. Let me know what you think, if you would like more planty blogs (ie not just animals) and if you fancy having a guest blog yourself (even if its just a great wildcreature shot).
IN SEARCH OF A TREE, AND THE WONDERFUL PATH OF TAXONOMY. (a glimpse into the process of naming and sourcing original references of a plant).
There is a set of stairs and a path that leads from Shek Lei Hang Village to Kam Shan Ridge (exits at the ridge between Kam Shan and the TV Tower Hill), a steep climb to some 300 metres or more above sea level, with apparently close to 1000 steps. Whilst the steps haven't been counted I rely on the poor soul who chalked up the numbers on the steps themselves, every 100 steps or so. The final ascent to Kam Shan, along the ridge, will consume the remaining metres to get you to 369 m above sea level. At around the 280 metre mark there is a grove of small trees, some reach 3 metres in height but most barely make it to 2.5 metres. They are evergreen trees but do have periods of sparse foliage when their new leaves emerge. A tree and the new red leaves may be observed in the picture Figure 1. A., C. and E.
Figure 1. B. has a picture of a mature trunk of a 2 metre tree with a new shoot emerging from under the tough bark. In some cases plants respond to low levels of soil Phosphorous by delaying the greening in their new leaves. In this case I cannot be sure this is the underlying principle behind the red new leaves as the soil is course gritty sand, covering clay and then rock, the rock probably close to the surface (Upper Jurassic Period Granite). There is a reasonable amount of debris, dead organic matter, in the top soil and I would have thought the clay might store a sufficient quantity of Phosphorous. This is something to be looked into on another occasion.
Figure 1. D. is the small tree coming into flower, the flowers being white to cream and rarely yellow, unless they are quite aged and almost ready to fall. It was in 2014 that I first noticed this group of trees and it wasn't until 2018 that a serious study of the species was undertaken. Part of that work is detailed here where I use some of the 2015 photographs, taken without the hindsight of my recent advances in photography techniques.
SO WHAT IS THIS TREE?
The tree in question used to belong to the family Theaceae (Camelias, Pyrenarias, Polyspora(Gordonia), Schima) and due to the Angiosperm Phylogeny Groups work in 2009 (APG III) has been moved to the family Pentaphylacacaeae. Pentaphylax was an original genus in the Pentaphylacacaeae but now Adinandra, Ternstroemia, Cleyera, Annelsea, and Eurya have all been moved into this family from the Theaceae. The Flora of Hong Kong Vol I. has not yet been revised since it came out around 2007.
In 2016, a scientific paper came out that further supported this move between families. (The Intra-familial Relationships of Pentaphylacaceae s.l. as revealed by DNA Sequence Analysis Biochemical Genetics 54(3) February 2016.)
TO BE CONTINUED....tomorrow....