Infrageneric Placement
In 1870, George Bentham published the first infrageneric arrangement of Adenanthos in Volume 5 of his landmark Flora Australiensis. Bentham divided the genus into two sections, placing A. sericea in A. sect. Stenolaema because its perianth tube is straight and not swollen above the middle. This arrangement still stands today, though A. sect. Stenolaema is now renamed to the autonym A. sect. Adenanthos. Bentham also published a variety, A. sericea var. brevifolia (now A. macropodianus) based on specimens collected from Kangaroo Island in South Australia.
This broad view of A. sericea continued into the 20th century, with several other species included in it, including A. oreophila and A. cygnorum. The current, narrower circumscription originated with Nelson's 1970 investigation of Adenanthos. Nelson was interested in the problem of why there are so many plant species with disjunct distribution patterns in southern Australia. One such species was A. sericea, the Kangaroo Island form of which occurred about 2500 km (1600 mi) east of the nearest population of the Western Australian variety. This led Nelson to undertake a full taxonomic revision of Adenanthos, in the course of which he concluded that the Kangaroo Island form of A. sericea warranted species rank, primarily because leaves are much smaller and have fewer laciniae than the Western Australian A. sericea. In 1978 he published A. macropodiana and synonymized A. sericea var. brevifolia with it. He also published A. oreophila and clarified confusion between A. sericea and A. cygnorum. Finally, Nelson refined Bentham's arrangement by dividing A. sect. Adenanthos into two subsections, with A. sericea placed into A. subsect. Adenanthos for reasons including the length of its perianth. However Nelson discarded his own subsections in his 1995 treatment of Adenanthos for the Flora of Australia series of monographs. By this time, the ICBN had issued a ruling that all genera ending in -anthos must be treated as having masculine gender; thus the specific epithet became sericeus.
The placement of A. sericeus in Nelson's arrangement of Adenanthos may be summarised as follows:
- Adenanthos
- A. sect. Eurylaema (4 species)
- A. sect. Adenanthos
- A. drummondii
- A. dobagii
- A. apiculatus
- A. linearis
- A. pungens (2 subspecies)
- A. gracilipes
- A. venosus
- A. dobsonii
- A. glabrescens (2 subspecies)
- A. ellipticus
- A. cuneatus
- A. stictus
- A. ileticos
- A. forrestii
- A. eyrei
- A. cacomorphus
- A. flavidiflorus
- A. argyreus
- A. macropodianus
- A. terminalis
- A. sericeus
- A. sericeus subsp. sericeus
- A. sericeus subsp. sphalma
- A. × cunninghamii
- A. oreophilus
- A. cygnorum (2 subspecies)
- A. meisneri
- A. velutinus
- A. filifolius
- A. labillardierei
- A. acanthophyllus
Read more about this topic: Adenanthos Sericeus, Taxonomy