Sirodotia assamica Necchi, N.L.Rossignolo, F.Yasmin, J.A.West & Ganesan

(Fig. 4 A-E)

Phytotaxa 437: 125 (2020).

TYPE. — F. Yasmin, 25.II.2019 (holo-, SJRP [SJRP 32584]).

TYPE LOCALITY. — India, Assam, Nagaon District, Chapanalla; 26°19’13.7”N, 92°10’16.5”E.

ADDITIONAL SPECIMENS EXAMINED. — SJRP 32583, SJRP 32585 (Appendix 1).

DISTRIBUTION. — Asia, India (northeastern).

REPRESENTATIVE DNA SEQUENCES. — COI-5P (MN508239, MN508240) and rbc L (MN496129, MN496130).

Description

Plants dioecious or monoecious; whorls 400-665 µm in diameter; primary fascicles, 6-11(-12) cells; proximal cells cylindrical or ellipsoidal; distal cells obovoidal or ellipsoidal; secondary fascicles abundant, covering the entire internode; spermatangia spherical, arranged in clusters on primary or secondary fascicles, 6-8 µm in diameter; carpogonial branches straight or slightly curved, short, composed of 1-5(-6) discor barrel shaped cells; arising from periaxial cells of primary fascicles, 7-23 µm in length; carpogonia with sessile, elongate cylindrical, ellipsoidal or lageniform trichogynes, 37-64 µm in length, 10-14(-16) µm in diameter; gonimoblast initial developing from the protuberant side of the carpogonium; gonimoblast filaments with erect branches of 1-4 cells; carposporangia obovoidal, 11-14 µm in length, 6-8 µm in diameter.

Remarks

A distinguishing feature of Sirodotia assamica is the occurrence of spermatangia arranged in clusters, thus far not confirmed for any other species of Sirodotia . It is most closely comparable to S. delicatula based on other vegetative and reproductive characteristics and its occurrence in or near India (Appendix 6). Sirodotia assamica differs from S. delicatula in having spermatangia in clusters, larger whorls (400-665 µm versus 137-433 µm in diameter), distal fascicles cells ellipsoidal or obovoid (L/D 1.3-2.1) in S. assamica and subspherical or obovoid (L/D 1.1-1.7) in S. delicatula and the known geographic distribution restricted to northeastern India.