# 芒花白頭那幾週，水田裡的蕨轉紅了

- URL: https://justfly.idv.tw/%e8%8a%92%e8%8a%b1%e7%99%bd%e9%a0%ad%e9%82%a3%e5%b9%be%e9%80%b1%ef%bc%8c%e6%b0%b4%e7%94%b0%e8%a3%a1%e7%9a%84%e8%95%a8%e8%bd%89%e7%b4%85%e4%ba%86/
- 日期: 2026-10-14
- 分類: 我知故我在
- 標籤: 山芙蓉, 芒花, 蕨類, 霜降

![芒花白頭那幾週，水田裡的蕨轉紅了]
霜降三候之一叫「草木黃落」。北臺灣的山頭從十月底開始換顏色，換的不是落葉，是草。整面坡的芒，一夜之間像被撒了麵粉。

##### 芒：先紫後白的頭

芒（Miscanthus sinensis，禾本科 Poaceae）是臺灣原生，從低地到高山的開闊草坡都找得到，2017 臺灣維管束植物紅皮書列為「國家暫無危機（NLC）」。圓錐花序羽毛狀，穗初帶紫紅色，轉為銀白。拍到一片白的照片很多，拍到紫紅色穗頭的照片少，因為時間窗口短，早一點紫，晚一點就全白了。

草嶺古道（新北貢寮）2026 芒花季訂在 10/31–11/29，由東北角及宜蘭海岸國家風景區管理處主辦。陽明山的芒花季是「每年 10 月～12 月」，擎天崗、金包里大路、大屯山頂、小油坑都算。冷水坑出發、經柳杉林上坡到擎天崗草原、再由城門下金包里大路，這條路線被形容成「秋季限定版的芒花」。iNaturalist 臺灣觀察紀錄裡，芒標註「開花」的以 11 月最多，看花的時間和記錄的時間，差不多對得上。

##### 山芙蓉：一天走完白到粉紅

山芙蓉（Hibiscus taiwanensis，錦葵科 Malvaceae）是臺灣特有種，紅皮書同樣是 NLC。臺大植物標本館的描述是中低海拔山區的灌叢，「up to 2,000 m」。花的把戲在一天之內：初為白色，午後稍帶粉紅，下午變成粉紅。別名叫三醉芙蓉，早上看到白花、傍晚回頭看到粉花，容易以為是兩種樹。

觀察紀錄的「開花」，10 月 20 筆，11 月 72 筆，11 月是全年最多。臺南西拉雅風景區梅嶺山區有報導說，每年 11 月芙蓉花開時，一棵樹能結上千個花苞。順帶一句：「拒霜花」是木芙蓉（Hibiscus mutabilis）的別名，山芙蓉不用這個名字，兩者別混。

##### 呂宋莢蒾：紅果是寫給鳥的

低海拔的林緣與灌叢裡，呂宋莢蒾（Viburnum luzonicum，五福花科 Adoxaceae）的果子這時候紅了。臺灣原生、非特有，紅皮書 NLC。果期 7–11 月，TaiEOL 的用途欄寫著「食草、蜜源、誘鳥」。南投竹山杉林溪的紀錄是「10~11 月果實成熟呈鮮紅到紫紅色」，觀察紀錄的「結果」10 月 82 筆、11 月 93 筆，同樣是全年最高。

果實是小而圓的核果，聚成平頂的一串，不是莓果。紅色在綠葉裡是招牌，對象是路過的鳥。看了覺得好看，算順便。

##### 水田與埤塘：不開花的那一群

山上在開花，水邊這群根本不開花。水蕨（Ceratopteris thalictroides，鳳尾蕨科 Pteridaceae）是[蕨類](https://zh.wikipedia.org/zh-tw/%E8%95%A8%E9%A1%9E%E6%A4%8D%E7%89%A9)，以孢子繁殖，長在水田、沼澤和緩流溪邊，紅皮書 NLC。臺大標本館記載葉片大小變化大，通常 10–35 cm，孢子葉比營養葉長得多；細長直立的那種，就是在忙著生孢子。

漂在水面的是滿江紅（Azolla pinnata，槐葉蘋科 Salviniaceae），多年生的漂浮型水生蕨類，逆境下葉片由綠轉紅，天一冷，整片水面就泛紅。葉片背側的葉腔裡住著藍綠菌（Anabaena azollae），能把空氣中的氮[固定](https://zh.wikipedia.org/zh-tw/%E5%9B%BA%E6%B0%AE%E4%BD%9C%E7%94%A8)下來。亞洲稻作中，它可以與水稻同田種植，或翻入土中當綠肥，這是 PROSEA 的國際資料，不是臺灣在地的做法紀錄。

要小心的是名字。《台灣植物誌》記載臺灣只有一種原生滿江紅，也就是 A. pinnata，紅皮書評為「資料缺乏（DD）」。但近年野外較常見的是歸化種（A. mexicana 與 A. microphylla 複合群），族群有增加趨勢。田裡一片紅色的浮萍狀蕨，多半不能直接認定是原生那一種，確認得靠專業鑑定。

在《金蘋果樂園》裡，牧靈人這一季也會遇到它們。

— 溫以君

### When the Silvergrass Goes White, the Paddy Ferns Turn Red

One of the three pentads of Frost’s Descent, a solar term in the traditional Chinese calendar, is called “grass and trees yellow and fall.” In northern Taiwan, the hills begin changing color at the end of October. The change comes from the grass. Whole slopes of silvergrass go white as if flour had been thrown over them overnight.

##### Silvergrass: purple first, then white

Silvergrass (Miscanthus sinensis, family Poaceae) is native to Taiwan and grows on open slopes from the lowlands to the high mountains. The 2017 Red List of Vascular Plants of Taiwan lists it as Not Threatened at the national level (NLC). The feathery panicles start out purplish red and turn silvery white. Photos of the white are plentiful. Photos of the purple are rare, because the window is short: a little early and the plumes are purple, a little late and they are all white.

The 2026 silvergrass festival at Caoling Historic Trail, a historic trail on the northeast coast in Gongliao, New Taipei, runs from 10/31 to 11/29. On Yangmingshan, the volcanic national park on the northern edge of Taipei, the silvergrass season runs “every year from October to December,” with spots including Qingtiangang, the Jinbaoli Trail, the Datun summit and Xiaoyoukeng. One route leaves from Lengshuikeng, climbs through a cedar forest to the Qingtiangang grassland, then descends the Jinbaoli Trail, and is billed as “autumn-limited silvergrass.” In Taiwan observations on iNaturalist, silvergrass flowering records peak in November, so the viewing season and the recording season line up roughly.

##### Taiwan hibiscus: white to pink in one day

Taiwan hibiscus (Hibiscus taiwanensis, family Malvaceae) is endemic to Taiwan, also NLC on the Red List. The National Taiwan University herbarium describes it as growing in thickets at low to middle elevations, “up to 2,000 m.” The trick is in a single day: the flower opens white, turns slightly pink in the afternoon, and is pink by late afternoon. Its Chinese nickname means “three-times-drunk hibiscus.” White flowers in the morning and pink ones in the evening could easily pass for two different trees.

Flowering records number 20 in October and 72 in November, the highest of any month. One news report from the Meiling mountain area in Tainan’s Siraya scenic area says that each November, when the hibiscus blooms, a single tree can set over a thousand buds. One naming caution: the Chinese name “拒霜花” belongs to a different species, Hibiscus mutabilis, not to this one.

##### Luzon viburnum: red fruit for passing birds

At low-elevation forest edges and in thickets, the fruit of the Luzon viburnum (Viburnum luzonicum, family Adoxaceae) is turning red now. It is native but not endemic, again NLC. Its fruiting season is July to November, and the Taiwan Encyclopedia of Life lists its ecological uses as “forage, nectar source, bird-attracting.” At Shanlinxi in Nantou, the record says the fruit ripens “bright red to purplish red” in October and November. Fruiting records number 82 in October and 93 in November, again the year’s highest.

The fruit is a small round drupe, clustered in a flat-topped bunch, and not a berry. Red against green leaves works as a signboard, and the intended readers are the birds going by. Human admiration is a side effect.

##### Paddies and ponds: the ones that never flower

While the hillsides flower, the plants at the water’s edge do not flower at all. The water fern Ceratopteris thalictroides (family Pteridaceae) is a [fern](https://en.wikipedia.org/wiki/Fern) that reproduces by spores. It grows in paddy fields, marshes and along slow-flowing streams, and is NLC on the Red List. The herbarium notes that fronds vary widely in size, usually 10–35 cm long, with fertile fronds much longer than sterile ones. The slim upright ones are the fronds busy making spores.

Floating on the surface is the mosquito fern Azolla pinnata (family Salviniaceae), a perennial floating aquatic fern whose leaves turn from green to red under stress. When the weather cools, whole stretches of water can turn red. In cavities on the underside of its leaves lives a cyanobacterium, Anabaena azollae, which fixes nitrogen from the air ([nitrogen fixation](https://en.wikipedia.org/wiki/Nitrogen_fixation)). In Asian rice farming it can be grown in the same field as rice or turned into the soil as green manure. That comes from PROSEA, an international source, and not from a record of local practice in Taiwan.

The name needs care. The Flora of Taiwan records only one native Azolla, A. pinnata, rated Data Deficient (DD) on the Red List. But the more common ones in the field in recent years are naturalized species (the A. mexicana and A. microphylla complex), and their populations are increasing. A red, duckweed-like fern across a paddy is, more often than not, not safe to call the native one without a proper identification.

In Golden Apple Paradise, the spirit herders also run into these plants this season.

— Wen Yi-chun