Isoetes lacustris

Common name: Quillwort
Scientific name: Isoetes lacustris 
Genus: Isoetes 水韭屬
Family: Isoetaceae 水韭科, quillwort family

Remarks:

Origin: native

Note: Isoetes lacustris, squillwort and Isoetes echinospora, spring quillwort looks very similar in appearance and they could occur in the same lake. They could only be distinguished accurately by microscopic examination of their megaspores. 

Reference: https://bsbi.org/learn/resources/plant-crib/isoetes

The following individuals seems to be the former one but it needs microscopic examination to confirm its identity. 

Date: 13th Aug

[177] A lot of quillworts found in shallow water of a lake. It is said that it is usually present in some quantity, forming a dense turf on deeper lake bottoms. (vs Isoetes echinospora, spring quillwort usually scattered though rarely forming continuous swards)

[174] A submerged evergreen aquatic plant. It is found in acidic, clear-water lakes from marginal shallows to about 5m. (The depth of the lake these plants were found was 3m in average.)

[181] A rosette of smooth, cylindrical, sheathing leaves.

[182] Upright, spreading clusters of more or less straight, rigid leaves emerging from a rooted 'corm'.

[180] Note that a water lobelia, Lobelia dortmanna 水生半邊蓮*  is found left to a quillwort and a comparison could be made between their apperances, especially their leaves. (Note '水生半邊蓮 ' is not an official chinese name for this species, it is only suggested by a Taiwanese website).

[178] Leaves erect, sometimes recurved 反曲的 (i.e. 葉端向外、向下翻卷) (vs leaves initially erect, but soon bending away from the centre of the rosette, often appressed to the substrate (looking starfish-like) in Isoetes echinospora, spring quillwort.) 

[154] A detached plant near the shore of the lake.

[165] More detached plants are found.

[166] Detached leaves are found as well.

[155] Leaves somewhat brittle, remaining stiff when taken out of the water vs
flaccid and clinging together when taken out of the water in Isoetes echinospora, spring quillwort.) 

[164] Leaf 10-45 cm long, c. 2.5-12 mm wide, cylindrical to varying degrees. (vs leaf
3-25 cm long, c. 2.5-3 mm wide near the base, with a perceivably slightly flattened adaxial face in soetes echinospora, spring quillwort.)

[173] Take a detached plant from the shore to have a closer examination.

[172] The lower part of the leaves are white and a bit transparent (It is white maybe because it died for a while) . It seems there are some transverse septum found along the whole length of the leaves.

[159] Middle part of a leaf, it becomes more greenish.

[154_1] Leaf parallel-sided and tapering only slightly (abruptly tapered) in the last few centimetres towards a rather blunt asymmetrical point (vs tapering almost immediately from the base to a slender, acute apex (tapering gradually to an cute tip) in soetes echinospora, spring quillwort.)

[154_2] Tapering abruptly at the leaf apex.

[157] Upright, spreading clusters of more or less straight, rigid leaves emerging from a rooted 'corm'.

[160] Leaf base is spoon-shaped, reviewing its true identity as a quillwort. The photo above also show the fibrous roots.

[158] Another closer examination to show the swollen leaf base.

[162] Need to peel off the outer leaf (sporophyll 孢子葉) to see the sporangium.

[162_1] Photo cropped above to show the ligule (Li), megasporangium (Mm) and megaspores (Me) found at the inner surface of leaf base. 

[162_2] A much more magnified photo to show the megaspores (orange dashed line).

Megaspores 500-570 micrometres diameter, the mature spore wall showing anastomosing 網結的 that resemble brain-coral ridges (x20 lens) (vs megaspores 420-450 micrometres diameter, densely spiny on all faces (x20 lens, only seen when dry and mature, i.e. late summer and autumn) in soetes echinospora, spring quillwort.)

[170] Another leaf come from a washed-up specimen.

[170_1] Cropped photo above to show the megasporangium (Mm) and megaspores (Me).

Sparganium angustifolium 線葉黑三棱

Common name: Floating Bur-reed
Scientific name: Sparganium angustifolium 線葉黑三棱
Genus: Sparganium 黑三棱屬*

Family: Typhaceae 香蒲科, cattail family

Note: Sparganium 黑三棱屬 is placed in Sparganiaceae 黑三棱科 in Cronquist system, of 1981. The APG II system, of 2003 (unchanged from the APG system, 1998), also recognizes this family. By the APG III system of 2009, Sparganium had been found to be fairly closely related to Typha 香蒲屬, and so was placed with that genus in family Typhaceae 香蒲科.

Origin: native

Date: 7th Aug (at 745m elevation) &13th Aug (at another location at 665m elevation)

[178] A large cluster of floating bur-reed in this lake of 745m elevation. It could be found in clear, nutrient-poor, organic-rich, acid or neutral upland lakes; to 1005m. 

[179]  Parts of the leaves, some bracts of the inflorescence are floating on the lake, with inflorescence erecting from the water surface.

[177] Rhizomatous perennial. Stem long, slender, submerged or floating, to 100cm. Note those floating on the water surface of the above photo are either the long leaves or the bracts of the inflorescence. Stem are those part of the plant below the inflorescence and are seen under the water.   

[171_1] An individual plant in the middle of the above photo. It is fruiting already and male flower heads withered and dropped off. Bracts (Br) are leaf-like, erect from the water surface first and then bend and float on the water. Leaves (L) are even longer and the upper parts of the leaves are floating on the water. Leaf base (Lb) could be seen in the above photo.

[171_2] Photo cropped above to show the inflated leaf base (Lb) with sheathing. (St: stem) Leaves are alternate and basal.

[173] Another plant with cropped photo below.

[173_1] Cropped photo showing the leaf without keel or midrib.(vs stem leaves keeled at base in Sparganium emersum 小黑三棱, unbranched bur-reed.) (Br: bract; L: leaf; St:stem). 

Stems are erect, green and smooth.

[082] (at another location at 665m elevation) It is perhaps the environment here is cooler than those plants found at 745m above and so male and female flowers are still flowering now.

[085] (at another location) Leaves all floating on the surface, linear, 30-80cm x 2-4mm (4 feet long, to ¼ inch (2 to 6 mm) wide), hairless, toothless, flat on the upper surface, flat to convex on the lower.

(vs stem leaves triangular in section in Sparganium emersum 小黑三棱, unbranched bur-reed.)

 Surfaces are green, the lower surface with green parallel veins and no keel. Leaves become more translucent below the water's surface.

[086] (at another location) A plant without flower. The leaves are so long that the upper part of them are floating on the water surface whereas the lower part are submerged and in upright position. 

[097]  (at another location) A lot of flowering plants with both male and female heads could be seen emerged from the water.

[100]  (at another location) An individual plant in the middle of the photo above, with flowering inflorescence rising from the water surface.

[097_1] (at another location) Flowering stems rise slightly above the surface of the water.  Inflorescence unbranched. (vs inflorescence branched in Sparganium erectum 直立黑三棱, branched bur-reed. )

The lowest bracts (leaf-like bract of lowest female head, i.e the red arrow above) is more than 10cm long and is 2.5-4 times as long as inflorescence (the blue arrow above). (vs leaf-like bract of lowest female head is less than 10cm long and is barely longer than the inflorescence in Sparganium natans 矮黑三棱, least bur-reed.)

(M1, M2 are male heads whereas F1, F2 and F3 are female heads.)

[093] (at another location) Male and female flower heads could be seen in this individual.

[093_1] (at another location) Round (male and female) flower heads in a spike-like arrangement at the top of the (main) stem, with separate male and female flower heads on the same plant (monoecious). (vs 6-9 male heads on branches in Sparganium erectum 直立黑三棱, branched bur-reed.)

 2-3 (2-4) stalkless male heads (2 above, M1 & M2), usually crowded and appearing as a single elongated terminal head. (vs 6-9 male heads on branches in Sparganium erectum 直立黑三棱, branched bur-reed.) (vs 4-7 male heads in Sparganium erersum 小黑三棱, branched bur-reed.) (vs 1 male head in Sparganium natans 矮黑三棱, least bur-reed.)

Each male head covered in dozens of petal-less flowers with 3 or more yellow-tipped white stamens. Male flower heads turn brown, wither and drop off after pollen release, the naked part of the stem usually persisting for a time but eventually also withering away; 

2-4 (2-5) female heads (3 above, F1, F2 & F3). are slightly larger than the males, and are single in the axils of leaf-like bracts, the upper head(s) stalkless, the lowest head(s) stalked with the stalk at least partially fused to the stem so the head looks attached to the stem above the axil (known as supra-auxillary 腋上生的). 

[166] Male flower heads are withering but female flower head could still be seen flowering right now for this individual.

[166_1] Photo cropped above to show the female flower head. Individual flowers have a single style at the tip of a green ovary and are surrounded by 3-6 scale-like tepals (petals with similar sepals) that lack a darker spot near the tip (could not be seen in the above photo, possibly need to dissect the flower head to examine them). (vs tepals dark-tipped in Sparganium erectum 直立黑三棱, branched bur-reed.)

Note the bracts (the leaf-like structure left to the female flower bead) inflated at base.

[164] As it is said before that these plants are found higher in altitude and perhaps the environment is warmer, flowers had finished. Male heads withered and fell apart whereas the female flower head is fruiting right now.

[164_1] Female flower head turns into fruit now. Female flower heads form densely packed seed heads that expand up to about 1 inch (to 30 mm) diameter, the plump 飽滿的, spiky head maturing from light green to reddish-brown. Fruiting heads up to ~1 inch (3 cm) diameter, fruit with straight beaks shorter than the body.

Note the lowest head(s) stalked with the stalk at least partially fused to the stem (see the blue arrows above) so the head looks attached to the stem above the axil (known as supra-auxillary 腋上生的). 

Erigeron sumatrensis 蘇門白酒草、野茼蒿

Common name: Guernsey Fleabane
Scientific name: Erigeron sumatrensis 蘇門白酒草、野茼蒿 *
Genus: Erigeron 飛蓬屬
Family: Asteraceae or Compositae 菊科, aster , daisy, composite or sunflower family

Remarks*: It was formerly named Conza sumatrensis 蘇門白酒草, belonged to Conza 假蓬屬、白酒草屬. It is also recorded in Hong Kong as an exotic plant. '茼蒿' is pronounced as '朣 hou1' in Cantonese.

Origin: Neophyte (established after 1500 AD). I It is a native of South America. It was first recorded in 1961 and was found naturalized in 1974.

Date: 4th Aug

[051] Annual or biennial herbs, 50-100 cm tall.

[052] Stem erect.

[041] Middle and upper leaves subentire or shallowly toothed.

[042] Middle and upper leaves gradually smaller upward, lanceolate to linear.

[043] All leaves pubescent on both surfaces.

[044] Note the hairy stem and lower surface of the leaves.

[043_1] Lower surface of the leaf.

[044_1] Forward hairs on leaf margin.

[046] Leaves in lower part oblanceolate or lanceolate, 5–15 × 0.5–2.5 cm, base attenuate 漸狹, apex acute, margin coarsely toothed or subentire.

[027] A pair of stipules at the base of the leaf. 

[029] Stems hirsute‑pubescent 粗毛兼被短柔毛的 throughout.

[029_1] Cropped photo above to show clearly the hairs.

[048] Stems hirsute‑pubescent 粗毛兼被短柔毛的 throughout. (Lower stem)

[048_1] Cropped photo above to show clearly the hairs.

[047] Basal leaves withered at flowering period. (Basal stem)

[047_1] Cropped photo above to show clearly the hairs.

[049] Capitula 頭狀花序 arranged in large panicle 圓錐花序.

[063]

[032] Flower buds.

[038]

[032_1] Flower buds.

[038_1] Flower heads (capitula 頭狀花序) 5-8 mm across,  ray florets with brownish petals, involucral bracts densely hairy.

(vs flower heads 3-5 mm across, white petals of the ray florets, involucral bracts glabrous in Erigeron canadensis 小蓬草、加拿大蓬、飛蓬、小飛蓬, Canadian Fleabane)

(vs flower heads 7-11 mm across, flower head clearly red tipped, involucral bracts hairy in Erigeron bonariensis 香絲草、野茼蒿、美洲假蓬、野地黃菊、蓑衣草、消息草, Argentine fleabane)

(vs flower heads 3-5 mm across, flower head with tendency to purple tips, involucral bracts with few hairs in Erigeron floribunda 多花飛蓬、多花飛蓮, Bilbao fleabane) 

[038_2] Heads 5-8 mm across, involucral bracts densely hairy

[014]

[056]

[014_1] Note there are 5 petals on disc florets. Ray florets pistillate 雌花的、具雌蕊的 and disk florets hermaphrodite.

[056_1] Note there are 5 petals on disc florets.(need to hold it in order to photo it clearly)

(vs 4-5 petals on disc florets in Erigeron canadensis 小蓬草、加拿大蓬、飛蓬、小飛蓬, Canadian Fleabane) 

(vs 5 petals on disc florets in Erigeron bonariensis 香絲草、野茼蒿、美洲假蓬、野地黃菊、蓑衣草、消息草, Argentine fleabane and Erigeron floribunda 多花飛蓬、多花飛蓮, Bilbao fleabane) 

[001] A possible pollinator -- a hoverfly belonged to Sphaerophoria 細腹食蚜蠅屬 spp, possibly a female Sphaerophoria scripta 短翅細腹食蚜蠅.