**5.** *Erigeron* **sect.** *Conyza*

Earlier we studied in detail morphological differences between species of the genus *Erigeron* that grow in Eurasia [30], and they are shown in **Table 4**.

Previously a hybrid of *Erigeron canadensis* and *E. sumatrensis—Conyza rouyana* Sennen—was described. A typical specimen of this taxon (P04315552), collected by F. Sennen in Catalonia in 1904, is kept in the herbarium of the Museum of Natural History in Paris [P] [7]. Nevertheless, some botanists did not recognize this hybrid and referred *C. royana* to *E. floribundus* [31], which is now treated as synonymous with *E. sumatrensis*. However, it cannot be excluded that morphological differences in several individuals could have been caused not by hybrid processes but by adverse environmental conditions.

The analysis of the **ITS1-ITS2** site of 16 samples of *Erigeron* sect. *Conyza* (supposed hybrids and parent taxa) confirmed our conclusions about the higher polymorphism of *E. sumatrensis* than *E. canadensis*: ITS1**-ITS2** sites of *E. canadensis* samples were identical, while *E. sumatrensis* has substitutions and ambiguous readings (**Table** 5). As for the supposed hybrids (samples 8a, 8b, 10a, 10b, and 22), only in one case an ambiguous reading of the nucleotides coincides with the substitution differentiating *E. canadensis* and *E. sumatrensis*, which indicates that the hybridization has taken place, but since in other cases the substitutions are identical (**Table 5**) and the supposed hybrids have no ambiguous readings, most likely, the reason for their morphological differences is the high polymorphism of *E. sumatrensis* taxon, to which they can be classified.


**Sample**

**107**

**Taxa** **65, 129, 136, 137,**

**72, 87,**

**83,**

**95 114 130, 567/**

**211-212 242 412 430 461,**

**249,**

**576/**

**568, 568/**

**584/**

**530/531,**

**500**

**503**

**521**

**536**

**560**

**558/559**

**469 471/472,**

**499/**

**502/**

**520/**

**535/**

**559/**

**598-600**

**585**

**569**

**404**

**577**

**238, 472/473,**

**570/571**

3 5a

5b

5c

6 16

8a

*E. sumatrensis* 

T T T T T

C

 A

 Y C T

 YY

 C C R G

C

 A

 C C T

 TC

 C C R G

C

 A

 Y C T

 YY

 C C G G

C

 A

 Y C T

 YY

 C C R G

C

 A

 Y C T

 YY

 C C R G

> *E. canadensis* (?)

> > 8b

10a

10b

22

13a 13b

18 19 20 *The nucleotides are coded using IUPAC* 

*Note: "E. sumatrensis E. canadensis (?)" – putative hybrids.*

**Table 5.** *ITS1-ITS2*

*polymorphism*

 *for different taxa of*

Erigeron *sect.* Conyza *in the* 

*Mediterranean.*

*E. canadensis*

*Erigeron* sp.

 C C *nomenclature.*

T

 C

 C C A

 CC

 C C G A

*E. canadensis*

C C C

T

T

 C

 C C A

 CC

 C C G A

 C

 C C A

 CC

 C C G A

T

 C

 C C A

 CC

 C C G A

T

 C

 C C A

 CC

 C C G G

 T A

 T A

 T A

 T A

 T A

 T C A C A T C A C A T C A C A T C A C A T C A C A

—

—

—

—

—

*Erigeron*

Т

C

 A

 C C T

 YY

 C C G G

—

—

—

—

—

—

—

—

—

—

—

C

A Y R C R TCT

C

A S R Y R TCT

C

A S R Y R TCT

C

A S R Y R TCT

C

A S G Y R TCT

C

A S R C A TCT

C

A S R Y R TCT

C

A S R Y R TCT

*Hybridogenic Activity of Invasive Species of Asteraceae DOI: http://dx.doi.org/10.5772/intechopen.91370*

> C

A C R C R TCT

C

A C R Y R TCT

C

A C R Y R TCT

*sumatrensis*

T T T T T

C

 A

 Y C T

 YY

 C C G G

C

 A

 C S T

 TC

 Y C R G

C

 A

 C C T

 TC

 Y C R G

C

 A

 C C T

 TC

 C Y R G

C

 A

 C C T

 TC

 C C R G

**Position in the alignment**

**no.**

#### **Table 4.**

*Diagnostic morphological features of* Erigeron *species.*


*Hybridogenic Activity of Invasive Species of Asteraceae DOI: http://dx.doi.org/10.5772/intechopen.91370*

assume that hybridization occurs in both directions in the Pskov population, but there is also a possibility that only one species may be maternal and the other paternal, and

*Invasive Species - Introduction Pathways, Economic Impact, and Possible Management Options*

Earlier we studied in detail morphological differences between species of the

F. Sennen in Catalonia in 1904, is kept in the herbarium of the Museum of Natural History in Paris [P] [7]. Nevertheless, some botanists did not recognize this hybrid

with *E. sumatrensis*. However, it cannot be excluded that morphological differences in several individuals could have been caused not by hybrid processes but by

The analysis of the **ITS1-ITS2** site of 16 samples of *Erigeron* sect. *Conyza* (supposed hybrids and parent taxa) confirmed our conclusions about the higher polymorphism of *E. sumatrensis* than *E. canadensis*: ITS1**-ITS2** sites of *E. canadensis* samples were identical, while *E. sumatrensis* has substitutions and ambiguous readings (**Table** 5). As for the supposed hybrids (samples 8a, 8b, 10a, 10b, and 22), only in one case an ambiguous reading of the nucleotides coincides with the substitution differentiating *E. canadensis* and *E. sumatrensis*, which indicates that the hybridization has taken place, but since in other cases the substitutions are identical (**Table 5**) and the supposed hybrids have no ambiguous readings, most likely, the

reason for their morphological differences is the high polymorphism of *E.*

0.1 6.1

*Е. bonariensis*

 0.1 5.2

The lower lateral deciduous axes of the inflorescence overturn the main shoot axis; the inflorescence covers the upper third of the shoot

Almost linear with 3

denticles

The leaves are gray-green, the pubescent leaves and stems are strongly pubescent with long silvery trichomes

– 5

–600 No more 30 less 500

*sumatrensis* taxon, to which they can be classified.

500

The main shoot is barely branched off and ends in a compound raceme occupying the upper third of the escape

> Linear-lanceolate with denticle margin

The leaves are light green, slightly pubescent, the stem is light green, strongly pubescent

*Diagnostic morphological features of* Erigeron *species.*

—was described. A typical specimen of this taxon (P04315552), collected by

*royana* to *E. floribundus* [31], which is now treated as synonymous

.

*rouyana*

*—Conyza*

*Е. sumatrensis*

 0.1 3.2 0.2

At the base, swollen

The lower lateral deciduous inflorescences are shorter than the main axis of the shoot; the diamond-shaped compound raceme is half the length of the generative shoot

Lanceolate-oval with a serrated margin

The leaves are dark green, softly pubescent, the stems are grayish with abundant soft pubescence

0.2 6.6

it is necessary to search for other, more variable sites of chloroplast DNA.

genus *Erigeron* that grow in Eurasia [30], and they are shown in **Table 4**

Previously a hybrid of *Erigeron canadensis* and *E. sumatrensis*

**5.** *Erigeron* **sect.** *Conyza*

adverse environmental conditions.

**Features** *E. canadensis*

4.8 0.1 2.4

Number of heads/ generative shoot

Diameter of heads, mm

Structure of shoot systems

Shape of leaves

Type of pubescence

**Table 4.**

**106**

Sennen

and referred *C.*

 *(?)"*

**Table 5.**

*ITS1-ITS2 polymorphism for different taxa of* Erigeron *sect.* Conyza *in the Mediterranean.*
