Evolutionary Biology

Alasemenia, the earliest ovule with three wings and without cupule

Deming Wang author has email address
Jiangnan Yang
Le Liu
Yi Zhou
Peng Xu
Min Qin
Pu Huang

Key Laboratory of Orogenic Belts and Crustal Evolution, Department of Geology, Peking University, Beijing 100871, China
School of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
Institute of Geology and Paleontology, Linyi University, Linyi 276000, China
Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China

https://doi.org/10.7554/eLife.92962.1

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Figures and data

Fertile branches and seeds of Alasemenia tria gen. et sp. nov.
a, Thrice dichotomous branch with a terminal ovule. Arrow indicating boundary between ovule and ultimate axis (PKUB21721a). b, f, g, i, Once dichotomous branch with a terminal ovule (PKUB21781, PKUB23132, PKUB19338a, PKUB17899). c, Twice dichotomous branch with a terminal ovule (PKUB19713a). d, e, Ovule with three integumentary wings (PKUB19321, PKUB19316). h, Ovule showing two integumentary wings (PKUB19282). j, k, Ovule terminating short ultimate axis (PKUB23114, PKUB23129). Scale bars, 1 cm (a-c, h), 5 mm (d-g, i-k).

Fertile branches and seeds of Alasemenia tria gen. et sp. nov.
a-c, Once dichotomous branch with a terminal ovule. a, b, Part and counterpart (PKUB16876a, b, PKUB17767). d, e, Part and counterpart, arrow showing the third integumentary wing (PKUB19322a, b). f, Ovule on ultimate axis (PKUB21752). g, h, k-m, Ovules lacking ultimate axis (PKUB16788, PKUB21631, PKUB16522 PKUB21647, PKUB21656). i, j, Part and counterpart, showing limit (arrows) between nucellus and integument (PKUB19339a, b). n, Four detached ovules (arrows 1-4) (PKUB19331). o, Enlarged ovule in n (arrow 2), showing three integumentary wings (arrows). Scale bars, 1 cm (n), 5 mm (a-h, k-m, o), 2 mm (i, j).

Seeds of Alasemenia tria gen. et sp. nov.
a, b, Part and counterpart, enlarged ovule in Fig. 1a (PKUB21721a, b). c, Enlarged ovule in Fig. 1c. d, Counterpart of ovule in c (PKUB19713b). e, Dégagement of ovule in d, exposing the base of the third integumentary wing (arrow). f, Enlarged ovule in Fig. 1d. g, h, Enlarged ovule in Fig. 2i, j, respectively. Scale bars, 5 mm (a-e), 2 mm (f-h).

Transverse sections of seeds of Alasemenia tria gen. et sp. nov.
a, b, Part and counterpart. c-e, Sections of seed in a and b (at three lines, in ascending orders). Arrow in d indicating probable nucellar tip (Slide PKUBC17913-12b, 10a, 9b). f, g, Part and counterpart. h-k, Sections of seed in f and g (at four lines, in ascending orders) (Slide PKUBC19798-8b, 6b, 4a, 4b). l, m, Part and counterpart. n-r, Sections of seed in l and m (at five lines, in ascending orders), showing three wings departing centrifugally (Slide PKUBC17835-5a, 7b, 8b, 9a, 10a). s, v, A, One seed sectioned. t, u, Sections of seed in s (at two lines, in ascending orders) (Slide PKUBC18716-8b, 7a). w-z, Sections of seed in v (at four lines, in ascending orders) (Slide PKUBC20774-7a, 6b, 3a, 3b). B-E, Sections of seed in A (at four lines, in ascending orders), showing three wings departing centrifugally (Slide PKUB17904-5b, 4a, 4b, 3b). Scale bars, 2 mm (a, b, f, g, l, m, s, v, A), 1 mm (c-e, h-k, n-r, t, u, w-z, B-E).

The mathematical analysis of wind dispersal ability of ovules with 1-5 wings.
The maximum windward area of each wing is S_wing and n represents the number of wings per ovule. r is the distance from the tip of wing to the axis of ovules. S(θ) represents the area of windward when the angle between airflow and wings is θ, and D(θ) represents the accumulated area of windward in a cycle. E_r(%) means relative efficiency. Red lines and expressions show the situation of n = 1.

Transverse sections of two seeds of Alasemenia tria gen. et sp. nov.
a-k, Serial sections of seed in Fig. 3a, b, at eleven levels and in ascending order (Slide PKUBC17913-13b, 12a, 12b, 11a, 11b, 10a, 10b, 9a, 9b, 8a, 8b). j, k, Arrows indicating integumentary lobes. l-x, Serial sections of seed in Fig. 3f, g, at thirteen levels and in ascending order (Slide PKUBC19798-11a, 9a, 9b, 8a, 8b, 7a, 7b, 6a, 6b, 5a, 5b, 4a, 4b). c, f, i, p, t, w, x, The same as those in Fig. 3c-e, h-k, respectively. Scale bars, 1 mm.

Transverse sections of one seed of Alasemenia tria gen. et sp. nov.
a-q, Serial sections of seed in Fig. 3l, m, at seventeen levels and in ascending order (Slide PKUBC17835-4b, 4a, 5b, 5a, 6b, 6a, 7b, 7a, 8b, 8a, 9b, 9a, 10b, 10a, 11b, 12a, 12b). d, g, i, l, n, The same as those in Fig. 3n-r, respectively. m-q, Arrows indicating integumentary lobes. Scale bars, 1 mm.

Transverse sections of two seeds of Alasemenia tria gen. et sp. nov.
a-d, Sections of seed in Fig. 3s, at four levels and in ascending order (Slide PKUBC18716-10a, 8a, 8b, 7a). e-i, Sections of another seed (at five levels, in ascending order) (Slide PKUBC18984-9b, 8b, 8a, 7b, 7a). c, d, The same as those in Fig. 3t, u, respectively. Scale bars, 1 mm.

Transverse sections of one seed of Alasemenia tria gen. et sp. nov.
a-l, Serial sections of seed in Fig. 3v, at twelve levels and in ascending order (Slide PKUBC20774-9a, 9b, 8a, 8b, 7a, 7b, 6a, 6b, 5a, 5b, 3a, 3b). e, h, k, l, The same as those in Fig. 3w-z, respectively. Scale bars, 1 mm.

Transverse sections of one seed of Alasemenia tria gen. et sp. nov.
a-j, Serial sections of seed in Fig. 3A, at ten levels and in ascending order (Slide PKUBC17904-6a, 6b, 5a, 5b, 4a, 4b, 3a, 3b, 2a, 2b). d-f, h, The same as those in Fig. 3B-E, respectively. Scale bars, 1 mm.

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