A novel angiosperm including various parts from the Early Cretaceous sheds new light on flower evolution

Figures & data

Figure 1. Geographical position of the locality of the Varifructus gen. nov in Liaoning, China (Drawn by X.W.). Reproduced from Han et al. (2017) with permission and courtesy of Acta Geologica Sinica (English edition). (a) Fossil locality (black dot) in northeastern China. (b) Detailed position of fossil locality Dawangzhangzi (black square) in a suburb of Lingyuan, Liaoning

Figure 2. Distal portion of the plant of Varifructus gen. nov, Ma007. Note the nodes (1, 2), a flower bud (3), and fruits of varying morphologies (4 − 9). Bar = 2 cm

Figure 3. Branching of Varifructus gen. nov. (a) Detailed view of Node 1 in Figure 2(a), which exhibits opposite axillary branching. Note the two subtending bisected leaves (black arrows) and axillary branches (white arrows). Bar = 5 mm. (b) Detailed view of Node 2 in Figure 2(a), which shows axillary branching. Note the subtending leaf (black arrow) and axillary branch (white arrow), on the counterpart. Bar = 2.5 mm

Figure 4. Fruit pair and flower bud of Varifructus gen. nov

(a) Detailed view of Fruit 8 in Figure 2(b), showing paired fruits (black arrows) connected at the base (white arrow). Bar = 5 mm. (b) Detailed view of flower bud (marked as 3 in Figure 2(a)) with peripheral foliar parts (white arrows). Bar = 2.5 mm. (c) Detailed view of the scars of the foliar parts (white arrows). Bar = 1 mm.

Figure 5. Fruit pair and its details

(a) Detailed view of a fruit pair (marked as 6 in Figure 2(a)), which shows connected leaves (white arrows), left fruits with a shared stout stalk (1.6 mm wide, between two black arrows), and the right single fruit with a slender stalk. Bar = 2.5 mm. (b) Detailed view of the right fruit in Figure 5(a) with a slender stalk (black arrows) and a connected leaf (white arrow). Bar = 2.5 mm. (c) Detailed view of the tip (arrow) of the right fruit in Figure 5(a). Bar = 1 mm.

Figure 6. Fruit pair and its details

(a) Detailed view of fruit pair (marked as 8 in Figure 2(b)), on the counterpart, showing the peripheral foliar parts (black arrows), right fruit with two seeds (white arrows) attached on the dorsal side (solid black arrow) of the fruit. Bar = 2.5 mm. (b) Detailed view of the fruit marked as 5 in Figure 2(a), showing the foliar part (white arrow) peripheral to the fruit (f). Bar = 0.5 mm. (c) Detailed view of the fruit marked as 5 in Figure 2(a), showing possible seeds (s) partially covered by the broken fruit wall. Bar = 0.5 mm. (d) Detailed view of one of the seeds/ovules in Figure 6a, showing the funiculus (black arrows) connected the dorsal of the fruit. Bar = 0.5 mm. (e) Detailed view of the fruit (tip to the left) marked as 4 in Figure 2a, showing the dorsal vascular bundle (arrows). Bar = 1 mm. (f) Detailed view of the lowest seed in the right fruit in Figure 6a, showing the megaspore membrane inside the seed. Bar = 0.5 mm. (g − i) SEM views of an in situ megaspore membrane. (g) A portion of a seed/ovule inside a fruit. Bar = 0.1 mm; (h) Tip of the seed/ovule in Figure 6 g, showing the margin (arrows) of the megaspore. Bar = 50 μm. (i) Cellular details of the megaspore membrane in Figure 6 h. Bar = 5 μm.

Figure 7. Fruit marked as 5 in Figure 2b (on the counterpart) and its details

(a) At least three fruits on the same stalk. Bar = 3 mm. (b) Detailed view of the rectangular region in Figure 7a, which shows the fruit wall covering the coalified content. Bar = 0.5 mm. (c) Detailed view of the leave marked as 9 in Fig. 2b. Bar = 2 mm Figure 8.

Figure 8. Reconstruction of Varifructus gen. nov

Table 1. Comparison between Varifructus gen. nov and other angiosperms from the Yixian Formation

Species	Sexuality	#seed/fruit	Seed attachment	Carpel arrangement	Stamen	Perianth	Reference
Varifructus	Female	2+	Dorsal	Whorled	?	Present	This study
Neofructus	Female	10–12	Ventral, dorsal	Helical	Unknown	None	Liu and Wang 2017
Archaefructus	Bisexual	2–12	Dorsal	Whorled, opposite	Present	None	Sun et al. 1998, 2002; Ji et al. 2004; Wang and Zheng 2012
Sinocarpus	Female?	~10	Ventral	Decussate	?	?	Leng and Friis 2003, 2006
Nothodichocarpum	Bisexual	7–8	Dorsal	Paired	Present	?	Han et al. 2017

Han G, Liu ZJ, Wang X. 2017. A Dichocarpum-like angiosperm from the early cretaceous of China. Acta Geol Sin. 90:1–8. doi:10.1111/1755-6724.13059.

 Google Scholar

Liu ZJ, Wang X. 2017. Yuhania: A unique angiosperm from the Middle Jurassic of Inner Mongolia, China. Hist Biol. 29(4):431–441. doi:10.1080/08912963.2016.1178740.

 PubMed Web of Science ®Google Scholar

Sun G, Dilcher DL, Zheng S, Zhou Z. 1998. In search of the first flower: a Jurassic angiosperm, Archaefructus, from Northeast China. Science. 282:1692–1695. doi:10.1126/science.282.5394.1692.

 PubMed Web of Science ®Google Scholar

Sun G, Dilcher DL, Zheng S, Zhou Z. 2002. Archaefructaceae, a new basal angiosperm family. Science. 296(5569):899–904. doi:10.1126/science.1069439.

 PubMed Web of Science ®Google Scholar

Ji Q, Li HQ, Bowe M, Liu YS, Taylor DW. 2004. Early Cretaceous Archaefructus eoflora sp. nov. with bisexual flowers from Beipiao, Western Liaoning, China. Acta Geol Sin. 78:883–896. doi:10.1111/j.1755-6724.2004.tb00210.x.

 Web of Science ®Google Scholar

Wang X, Zheng XT. 2012. Reconsiderations on two characters of early angiosperm Archaefructus. Palaeoworld. 21:193–201. doi:10.1016/j.palwor.2012.10.002.

 Google Scholar

Leng Q, Friis EM. 2003. Sinocarpus decussatus gen. et sp. nov., a new angiosperm with basally syncarpous fruits from the Yixian Formation of Northeast China. Plant Syst Evol. 241(1−2):77–88. doi:10.1007/s00606-003-0028-8.

 Web of Science ®Google Scholar

Leng Q, Friis EM. 2006. Angiosperm leaves associated with Sinocarpus infructescences from the Yixian Formation (Mid−Early Cretaceous) of NE China. Plant Syst Evol. 262(3−4):173–187. doi:10.1007/s00606-006-0461-6.

 Web of Science ®Google Scholar