Zygodon rupestris

The two common Zygodons, viridissimus (var. viridissimus) and conoideus are widespread and fairly common in VC41. Roy Perry described Zygodon viridissimus as a frequent epiphyte in the county (in NPT it is also found frequently on stone). In contrast Roy described Z. conoideus as rare, but probably overlooked and confused with viridissimus. Like other epiphytes it has probably increased greatly in the last few decades. Unlike Z. viridissimus it often produces capsules in early spring, which draws your attention. Zygodon rupestris wasn't listed by Roy in the county Flora, but, if our current records are sound, it looks as if it is widespread here and probably under recorded. 

Current MapMate records for Zygodon rupestris in Glamorgan

I can't remember ever seeing Z. viridissimus with capsules, but we do occasionally find rupestris in fruit which can lead to confusion with conoideus. The Atlas warns that confusion with conoideus may have led to errors in mapped records of rupestris. So it pays to check the gemmae which in my experience are always present in these 3 species and easily found if you mash up a few leaves on a slide. Zygodon conoideus usually produces lots of gemmae which are 7 or 8 cells long while the gemmae of rupestris are 4 or 5 cells long. The gemmae of Z. viridissimus are almost bullet-shaped and, uniquely, have longitudinal and transverse cell walls.

Zygodon viridissimus: bullet-shaped gemma with longitudinal and transverse cell walls; specimen epiphytic on Sitka Spruce, Pentreclwydau

Zygodon conoideus: cigar-shaped gemma with 8 cells (no longitudinal walls); specimen epiphytic on Grey Willow, Pentreclwydau

Zygodon rupestris: gemma with 5 cells (no longitudinal walls); specimen epiphytic on mature Ash, Ynysmeudwy