Calasterella D.G.Long & T.X.Zheng, 2023

Long, David G. & Zheng, Tian-Xiong, 2023, A new subfamily Calasterelloideae and new genus Calasterella for a phylogenetically and morphologically distinct member of the Aytoniaceae, Phytotaxa 606 (3), pp. 225-230 : 226

2. Calasterella D.G.Long & T.X.Zheng , gen. nov.

Type species: Calasterella californica (Hampe ex Austin) D.G.Long & T.X.Zheng comb. nov. (≡ Fimbraria californica Hampe ex Austin, Hepat. bor.-amer. 33, 1873).

Fig. 1 , 2 , 3

Description: Dioicous; thallus lacking odour when crushed, branching strictly dichotomous, differentiated into upper photosynthetic aerenchyma with irregular air chambers in up to 5 layers and ventral compact tissue with mucilage cavities, epidermis with simple air pores; ventral scales in two rows, each with 1–4 subulate appendages; gemma cups absent; rhizoids dimorphic; androecium cushioned, dorsal, not terminating vegetative growth; female receptacle ovoid, deeply 4(5)-lobed, with stout, longitudinally ridged stalk, terminal on main thallus, not terminating vegetative growth which continues as innovations from both apical lobes; involucre deeply cleft to base, sporophyte enclosed in pseudoperianth; spores lemon-yellow with conspicuous trilete ridges, prominent equatorial wing, similar ornamentation on proximal and distal surfaces, lacking large areolae but with fine network of alveolae.

Etymology: The genus is named by the combination of the abbreviation of its main distribution region “ California ”, and the previous placement “ Asterella ”.

Distribution: North America ( Mexico and United States).

Figures

FIGURE 1. Calasterella californica (Hampe ex Austin) D.G.Long & T.X.Zheng (≡ Asterella californica (Hampe ex Austin) Underw.).A. Male plant (W. T. Doyle 11445-b, E). B. Female plant (D.G. Long & J. Shevock 45892, E).

FIGURE 2. Calasterella californica (Hampe ex Austin) D.G.Long & T.X.Zheng.A–E.Ventral scales; F, G.Appendages of ventral scales; H. Carpocephalum showing pseudoperianths (lateral view); I. Carpocephalum showing pseudoperianths (dorsal view); J. Transverse section of stalk of archegoniophore.Arrow: pseudoperianths. [A: N. B. Kimber 2894 (NICH). B, G, H: E. G. McLaughlin s.n. (NICH). C, F: A. Carter 444 (NICH). D, I, J: W. B. Schofield 98595 (NICH). E: W. B. Schofield s.n. (NICH).]

FIGURE 3. Calasterella californica (Hampe ex Austin) D.G.Long & T.X.Zheng. A: Immature carpocephalum from below showing deeply cleft involucres with overlapping margins of cleft. B: Mature carpocephalum from below showing pseudoperianths and dehisced sporophyte with lemon-yellow spores. C: Scanning Electron Micrographs of the spores, distal face. D: Scanning Electron Micrographs of the spores, proximal face. Arrow heads: involucre.Arrow: spores. Scale bars: A, 2 mm; B, 1 mm; C, D: 20 μm. [A: D.G. Long 45940 (E). B: D.G. Long 45333 (E). C, D: D. G. Long et al. 44666 (E)]