The genus Cathaya is monospecific, comprising only the species C. argyrophylla.
From Bean's Trees & Shrubs
A new genus of conifers, discovered by Chinese scientists in Kwangsi province in 1955. For the following account we are indebted to Mr David Hunt of the Kew Herbarium:
Two living species native to S.W. China have been described, C. argyrophylla Chun & Kuang and C. nanchuanensis Chun & Kuang, the second from vegetative material only, and consequently of doubtful status. Neither has been introduced and no material has been available for study. A third species, first described as a Keteleeria, was found some fifty years before in fossil deposits in Germany.
Evergreen trees with branchlets of two kinds; long shoots with spirally arranged leaves, lateral short shoots with more or less whorled leaves. Branchlets ribbed with the decurrent bases of the linear leaves, the point of leaf-insertion slightly raised, as in Keteleeria or Pseudotsuga. Pollen grains with air-sacs. Female cone-scales persistent, i.e. the cones not breaking up at maturity.
The dimorphic shoots should not be taken to imply a particularly close relationship between Cathaya and the larches, cedars, and pines, as the foliar spurs of Cathaya are not of the same order of structural specialisation as in these other groups, and are apparently sterile, whereas in the larches and cedars at least, it is the long shoots which are sterile. Furthermore, dimorphism of the shoots is a feature which appears to have arisen independently in quite unrelated groups of the Gymnospermae such as Ginkgo, Phyllocladus, and Taxodium. Rather, the general morphology of the leaves, shoots, and cones of Cathaya implies a close relationship with several genera of the Abies group, Keteleeria and Pseudotsuga in particular coming to mind. In a paper on the wood anatomy (Yatsenko-Khmelevsky and Budkevich, in Journ. Bot. U.R.S.S., Vol. 43, pp. 477-80, 1958) general similarities with Picea and Pseudotsuga are shown (a comparison with Keteleeria does not appear to have been made) and Takhtajan is quoted as considering Cathaya nearest to Picea.