Introduction

An integrative view on the systematic position of the cupressophyte Cephalotaxus

“…Coniferopsida and Taxopsida, and included Cephalotaxaceae in the class Coniferopsida with only Taxaceae in the class Taxopsida. Sporne ( 1971 ), Stewart ( 1983 ), and Biswas and Johri ( 1997 ) made a similar treatment, both classified Cephalotaxaceae in the Coniferales and retained only Taxaceae in the Taxales. Cheng and Fu ( 1978 ) treated Cephalotaxus as a separate order Cephalotaxales intermediate between the Podocarpales and the Taxales in the class Coniferopsida.…”

“…Eckenwalder ( 2009 ) indicated “the fleshy outer layer of the seed coat intimately united with a surrounding fleshy aril that extends almost all the way to the tip.” Dörken et al ( 2019 ) also considered the fleshy part of Cephalotaxus as an aril homologous to the aril of the Taxaceae. Singh ( 1978 ) and Biswas and Johri ( 1997 ), however, contended that the differentiation of the mature integument into three layers, the outer sarcotesta becoming fleshy and forming the fleshy layer in Cephalotaxus , distinguishes it from the aril of the Taxaceae while showing similarities to the sarcotesta of cycads and Ginkgo L. Li et al ( 1986 ) stated that the seed of Cephalotaxaceae possesses no aril. We observed the structure and development of the seed coat development of Cephalotaxus (Figure 2a–h ), and agreed with Singh ( 1978 ), Biswas and Johri ( 1997 ), and Yang et al ( 2011 ) that the seed coat of Cephalotaxus at maturity is differentiated into three layers, viz.…”

“…Singh ( 1978 ) and Biswas and Johri ( 1997 ), however, contended that the differentiation of the mature integument into three layers, the outer sarcotesta becoming fleshy and forming the fleshy layer in Cephalotaxus , distinguishes it from the aril of the Taxaceae while showing similarities to the sarcotesta of cycads and Ginkgo L. Li et al ( 1986 ) stated that the seed of Cephalotaxaceae possesses no aril. We observed the structure and development of the seed coat development of Cephalotaxus (Figure 2a–h ), and agreed with Singh ( 1978 ), Biswas and Johri ( 1997 ), and Yang et al ( 2011 ) that the seed coat of Cephalotaxus at maturity is differentiated into three layers, viz. endotesta, sclerotesta, and sarcotesta; the sarcotesta is thus different from the aril in the Taxaceae in origin, the fleshy layer of the Cephalotaxaceae being part of the seed coat (developing from integument), while the aril of the Taxaceae is derived from a modification of bracts, for example, Pseudotaxus (Dörken et al, 2019 ).…”

“…He included Amentotaxus Pilg. and Cephalotaxus in the family Cephalotaxaceae, a treatment adopted by Page ( 1990 ), while many others treated them as two separate families and included Amentotaxus in the Taxaceae (e.g., Biswas & Johri, 1997 ; Cheng & Fu, 1978 ). Takhtajan ( 1953 ) classified conifers in the order Coniferales of the subclass Stachyosperminae and treated the Cephalotaxaceae and Taxaceae as two separate families.…”