(First upload on May 31 2016. Last on September 9 2018) [ 日本語 | English ]

Dryopteris crassirhizoma Nakai

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Dryopteris Adans. (オシダ)
Oshida (オシダ, 雄羊歯), wood fern
Memma (メンマ)
Lifeform: semi-evergreen or semi-deciduous perennial fern
Distribution: Manchuria - Korea - Japan (not in Kyushu)

Flora on Mount Usu

Habitat: mesic forest floor
Chromosome number: n = 41
f. maackii (Milde) Tagawa (キレコミオシダ)

An unidentified shoot, close to D. crassirhizoma,
in Sandaohu (三道湖) wetland, northeastern
China, on October 10 1989.

Developmental leaf architecture was quantitatively described in terms of measurements of various parameters on leaf blade from different size of sporophytes in Dryopteris monticola, D. tokyoensis and a putative hybrid, D. kominatoensis in the natural site of Hokkaido, to compare the ontogenetic differentiation in foliage structure among allied ferns. The morphological stage of leaf and sporophyte was tentatively quantified by the number of midrib branches of the leaf (NV, number of veins), which exhibited a significant correlation to the leaf-shape complexity from a circle (DI = marginal length/2 × (π × square)1/2) of leaf blade.
D. kominatoensis showed intermediate values between others in following characters; DI increase, maximum NV (also blade length), maximum number of costa branches of pinnae (NVMP), number of costa branches of the lowest pinna (NVLP), difference between NVMP and NVLP (NVMP-NVLP), during heteroblastic leaf development. A larger number of leaves per sporophyte was found in D. kominatoensis than in others. The fertility rate (%) and initiation of fertility (IF) in the relative developmental stage (RDS) of D. kominatoensis shifted to that of D. tokyoensis, while the order of pinnae with NVMP shifted to that of D. monticola. Even in the intermediate characters in D. kominatoensis, slight shifts in characters to those of putative parents were found during heteroblastic leaf development. (Sato T, Tsuyuzaki S 1988)

Dryopteris crassirhizoma in Hokkaido

[1/2] near a junglezym in Tomakomai Experimental forest on September 10 2009. [3] in Tsukiura Forest Park faced to Toya Lake on September 15 2015. [4] at a bakery in Ebetsu City close to Tsukigami Lake on October 8 2017.