Phycology جلبک شناسی

نخستین پایگاه اطلاعاتی جلبک شناسی به زبان فارسی

کلید شناسایی هتروکونتوفیتا Provisional key to Heterokontophyta

by C.S. Lobban & A.D.R. N'Yeurt


1. Thallus colonial, consisting of separate individual cells in a common matrix or tube: 2
1. Thallus multicellular, the cells closely adherent to one another: 6

Colonial heterokonts (Sarcinochrysidales and Bacillariphyceae)

2. Colony filamentous: 3
2. Colony globular: 4

3. Filaments comprising corrugated tubes containing very long, needle-like diatom cells: Nitzschia
3. Filaments with cells packed into it, only evident when colonies are kept at ~20C for a day or more, when they round up and separate: Chrysonephos

4. Colonies extremely fragile, disintegrating if picked up: Chrysocystis
4. Colonies rubbery or mucilaginous but easily handled: 5

5. Colonies rubbery golden, spherical cells distributed throughout matrix: Sarcinochrysis
5. Colonies very mucilaginous, mostly colorless with a powdery mustard-yellow surface dust; elongate cells with distinctive apex, on long mucilaginous stalks:

Multicellular (Phaeophyceae)

6. Thallus exclusively filamentous, generally in tufts or turfs: 7
6. Thallus not exclusively filamentous: 11


7. Filaments multiseriate (more than one row of cells), parenchymatous; pyramidal or globose or Y-shaped vegetative propagules commonly present: Sphacelaria
7. Filaments uniseriate (one row of cells): 8

8. Filaments tangled into rope-like tufts, “flowerlike” plastids, appearing to have four lobes with a central pyrenoid: Asteronema
8. Filaments not tangled and ropey; appearance fuzzy or silky: 9

9. Plurilocular sporangia commonly present, thallus brown or tan: 10
9. Sporangia entirely absent, zoids formed by cells in tube rounding up (may be induced by cold shock; see
3 above), thallus yellow-brown: Chrysonephos

10. Meristematic zone (dividing cells) distinct, generally at base of long unbranched filament; sporangia mostly stalked: Feldmannia
10. Meristematic zones
intercalary, diffuse, rarely at base of short lateral branch; sporangia mostly sessile (not stalked): Hincksia

11. Thallus of parenchymatous plates partially adherent to substratum or erect flat, terete or globose fronds: 12
11. Thallus crustose, pseudoparenchyma of filaments forming basal layer and erect carpet-like layer: 13

12. Thallus flat fan-shaped to strap-like blades: 14
12. Fronds terete (may be compressed/oval), globular or irregular:

crustose, uncalcified

13. Relatively thick crust, difficult to remove, basal layer 1-2 cells, erect filaments tightly adherent: Ralfsia
13. Thin crust easily removed, base 3-4 cells, erect filaments separating easily: Hapalospongidion

flat, erect/prostrate

14. Thallus calcified, erect broad to elongate fans with inrolled margins: Padina
14. Thallus not calcified, margins not inrolled: 15

15. Thallus fan-shaped or tapering markedly from apex to base; apical meristem diffused along the leading edge of the blade: 16
15. Thallus straplike, branches not tapering markedly; apical meristem a single cell or small cluster of cells: 18

16. Medullary cells uniformly rectangular, in stacked tiers: 17
16. Medullary cells not uniformly regular or stacked: Stypopodium

17. Cross section with a central medullary layer of cells bigger than other medullary and cortical cells; thick largely creeping plants often with ventral surface well anchored to substratum: Lobophora
     [Distromium looks like Lobophora but is 2 cells thick; not yet reported]
17. Cross section showing medulla of equal layers: Zonaria

18. Blades with distinct midrib: Dictyopteris
18. Blades without distinct midrib: 19

19. Growth from one apical cell per branch; medulla, at least near the apices, generally a single layer surrounded by a single layer of markedly smaller cortical cells: Dictyota
       (D. cervicornis recently transferred to Canistrocarpus)
19. Growth from multiple apical cells per branch; blades several cells thick without marked distinction between cortex and medulla: Spatoglossum


20. Thallus irregularly-shaped mass without distinct axes: 21
20. Thallus with one or many axes, having some consistent pattern to the branches or blades: 22

21. Thallus sac-like, often lobed, hollow when mature; margins not inrolled: Colpomenia
21. Thallus initially hollow, soon becoming flattened with many holes; margins inrolled: Hydroclathrus

22. Thallus floats when detached from substratum, possessing some type of air bladder; reproductive organs within sunken conceptacles: 23
22. Thallus sinks when detached from substratum, without air-bladders; reproductive organs on surface, not sunken in conceptacles; without leaflike or pyramidal branches: 25

23. Main axes terete, with leaf-like, terete, or pyramidal branches: 24
23. Main axes divided into leaf-like sections, each generally with a vesicle at the center: Hormophysa

24. Blades leaf-like; air bladders bulbous and obvious: Sargassum
24. Blades pyramid-shaped; air-bladders sunken within blades: Turbinaria

25. Tough, erect or matted thalli: 26
25. Thallus lax, irregularly branched; branches hollow, occasionally collapsed and somewhat flattened: Rosenvingea

26. Erect thalli with cryptostomata: Chnoospora
26. Creeping mat of narrow terete or compressed axes, cryptostomata absent: Padina (Vaughaniella stage)


Revised April 2006

نویسنده : رضا رمضان نژاد قادی ; ساعت ٤:٢۱ ‎ب.ظ روز سه‌شنبه ٢٧ امرداد ۱۳۸۸