满江红科 [Insert Pin Yin]
Ferns, usually small, floating. Stems prostrate or erect, very short and slender, easily broken, green, with protostele, pinnately branching or falsely dichotomously branching, normally decumbent and floating on surface of water, or lotuslike when growing in shallow water or in crowded situations up to 3–5 cm high above water surface. Fronds sessile, alternate, in two rows along upper side of stem, often imbricate, partite into dorsal (upper emersed) lobe and ventral (lower immersed) lobe; dorsal lobe floating on water surface, oblong or ovate, slightly concave abaxially at middle, densely papillose adaxially, green, fleshy, with a cavity near base containing blue-green algae (Anabaena); ventral lobe shell-like, membranous, tightly imbricate, transparent, colorless, or reddish and slightly incrassate near base; sometimes ventral lobe changing into and acting same as dorsal lobe when plant in erect growing state; lamina color changing from green to yellow or red depending upon environmental conditions (e.g., high temperature, lack of nutrients, salinity). Sporocarp usually in pairs, rarely 4-clustered, at base of lateral branches; megasporocarp located under microsporocarp, oblong or ovoid, containing one megasporangium producing one functional megaspore; megaspore topped with conic structure (indusium) covering 3–9 colorless spongelike floats and an Anabaena colony; microsporocarps globose or peachlike, large, 4–6 × megasporocarp, umbonate at apex, exine thin and transparent, containing majority of microsporangia, each microsporangium containing 32 or 64 microspores, embedded in 5–8 colorless masses, covered with different attachments according to different species.
One genus only in the family; ca. seven species worldwide, tropical to temperate regions.
满江红属 [Insert Pin Yin]
Carpanthus Rafinesque; Rhizosperma Mayen.
Characters of the family. Basal number x = 22.
About seven species: Africa, Americas, Asia, Europe, Oceania; two species in China.
1a. Megasporangia with 9 floats on exine, maculae of microsporangia with few single or irregular branch silklike hairs, lateral branch distinctly axillary and numbers same with frond numbers .... 1. A. imbricata
1b. Megasporangia with 3 floats on exine, maculae with numbers of anchorlike hairs, lateral branch out of axils and numbers less than frond numbers ................................................................. 2. A. filiculoides
满江红 man jiang hon
Salvinia imbricata Roxburgh ex Griffith, Calcutta J. Nat. Hist. 4: 469[??470]. 1844; Azolla imbricata var. prolifera Y. X. Lin; A. imbricata var. sempervirens Y. X. Lin; A. pinnata R. Brown var. imbricata (Roxburgh ex Griffith) Bonaparte.
Plants small, floating, outline ovate or triangular. Stems slender and creeping, lateral branches axillary, falsely dichotomous, with downward growing fibrous roots. Fronds as small as sesame seeds, alternate, sessile, imbricate in two rows, trapezoidal blade parted into dorsal lobe and ventral lobe; dorsal lobes green, or usually becoming purplish after autumn, oblong or ovate, cormous, colorless at margin, densely papillose, a cavity near base contains ‘Anabaena’ inside; ventral lobes cell-like, colorless and transparent, ± purplish red, obliquely submersed. Sporocarps in pairs; megasporocarps small, narrowly ovate, beaklike at apex and containing a megasporangium, containing only one megaspore, 9 floats in two rows attached around megasporangium, upper 3 floats larger, lower 6 floats smaller; microsporocarps large, globose or peachlike, with one short beak at apex, exines thin and transparent, containing majority of long-stalked microsporangia and each containing 64 microspores, microspores individually embedded in 5–8 masses, masses with silklike hairs on surfaces.
Floating on ponds, paddy fields, irrigation ditches. Widely distributed in Yangzi River valley region in mainland China, Fujian, Guangdong, Guangxi, Henan, Shandong, Taiwan [Japan, Korea, Vietnam; Africa, Asia, Australia, Pacific islands].
The whole plant of Azolla imbricata is used as green manure and forage; it is used as medicine to induce perspiration, promote dieresis, expel wind-evil, and remove wetness-evil and neuro-dermatitis.
This species has been long cultivated as a fertilizer (upon decomposition) in rice paddies of southeast China.
Azolla imbricata is sometimes divided into varieties as follows: var. imbricata: dorsal lobes turning from green to reddish from autumn to winter or during hot summer time; plants usually not or producing few sporocarps and vegetatively reproducing; widely distributed in Yangzi River valley and region and Taiwan [Japan, Korea]; and var. sempervirens Y. X. Lin: plants green always, ventral lobes not purplish red; Fujian, Guangdong, Guangxi [Vietnam]; var. prolifera Y. X. Lin: plants producing a lot of sporocarps during autumn and dying in winter and reproducing by spores following year; Henan, Shandong.
细叶满江红 xi ye man jiang hon
Plants more robust than Azolla imbricata. Lateral branches axillary, numbers of lateral branches less than fronds of stem; when growing in shallow water to wet places or plants in crowded state, stems becoming erect and dorsal lobes change to ventral ones. Sporangium with 3 floats on exines; massulae of microsporangium covered with anchorlike hairs.
Cultivated and escaping, rice fields, ponds, ditches. Widely distributed in Yangzi River valley and region, S China [??provinces] [NE Asia, Europe, North and South America, Pacific islands].
The whole plant of Azolla filiculoides is used as green manure and forage.